Progress 07/01/12 to 06/30/17
Outputs
Target Audience:Accomplishments of my activities toward proactive and reactive approaches to herbicide-resistant weed management are divided by audience and are noted as follows: Farmer audience Awareness of the impact and need for prevention of herbicide-resistant weed species continues to grow. Information and education on addressing herbicide resistance and tactics to increase chemical and cultural diversification are in greater demand and data generated in cooperation with the agrichemical industry is available at our Applied Weed Science Web Site at http://appliedweeds.cfans.umn.edu/ and management strategies and tactics are available at the Extension Web Site: https://extension.umn.edu/crop-production#weed-management. I was involved in farmer focused events to discuss some of the work that I have been doing with the Weed Management Team at multpile locations (attendance across locations totaled ~500). Four of these events were devoted to in-depth education using in-field research and demonstration field trials to assist farmers and those who influence farmers (retail dealers and the agricultural press) in making weed management decisions based on weed biology, ecology and agronomics. I am also working on a NIFA grant surveying herbicide resistance attitudes and management practices of farmers. Our team of weed scientists, sociologists and economists are continuing to investigate the results of our listening sessions and a national survey and our findings are beginning to be published. I was involved in establishing two farmer listening sessions in MN that were facilitated by a sociologist and I contributed to the nation-wide survey instrument. Focus group results from a diverse set of states show that farmers are reluctant to discuss a neighbor's poor weed management practices with that neighbor and one lesson for extension efforts is that lack of awareness is not an adoption barrier, while time constraints, faith in new technologies, and reticence to tell others "how to farm" are more important constraints. Advisors to farmers Crop advisors are a critical connection to farmers. I was an instructor at five of the six Ag Professional Update Sessions held in: Kasson, Lamberton, Morris, Waseca and Willmar, MN (attendance at the five sessions was 278). The attendees influence agricultural practices on 5.5 million acres. I established the curriculum and served as lead instructor at the Ag Professional Field School, a two-day event held this summer on the Saint Paul campus. I was responsible for developing hands-on field plots and curriculum for two sessions that focused on "The Principles and Symptomology of Herbicide Mode of Action (HMOA)" and "Dicamba soybean technologies" The field-school effort is very time intensive during a very busy time of the year. The educational activities on day 1 were four in-depth 1.5-hour sessions repeated 4 times so all participants were involved in each session - this included the HMOA session. Attendance at my sessions was 120 for day 1 and 68 out of a potential 120 attendees for day 2. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
In order to stem the advance of herbicide resistant weeds, management practices have to become less herbicide-centric and more diverse. Education efforts continue in this critical area by addressing the interaction of weed biology, ecology and agronomics with the interaction of economics and sociological factors. Early in 2017 I served as co-coordinator of an 11-Midwest state farmer listening session funded by APHIS; we were one of seven locations. The purpose was to gather input regarding farmer perceptions and barriers to adoption of integrated weed management practices. Two manuscripts have been submitted to Weed Science regarding our findings and I will serve on a panel discussion discussing this effort at the WSSA meeting in February, 2018. Our NIFA- funded team of weed scientists, sociologists and economists are beginning to report on our findings via conferences and symposia and are in the process of developing numerous manuscripts that will be published in weed science, economic and sociology journals. The findings from the barriers to adoption research has already begun to inform and influence my Extension programming via a University of Minnesota Extension program series titled - Strategic Farming - Growing Soybeans that Out-Compete Weeds. An impact statement follows: Issue - Soybean farmers are increasingly dealing with weed populations resistant to multiple herbicide groups. The number of weed species with resistance to herbicides has risen dramatically in recent years. As a result, more time and money is spent on weed control; farmers face the likelihood of lower yields and profits unless changes in their weed management are implemented. What was done? -From January to March 2018, ten "Strategic Farming - "Growing Soybeans that Out-Compete Weeds" programs were presented across Minnesota for 541 people. This was a great increase from the pilot program that was launched last year in six locations for 70 people. The goal of the program was to help farmers and ag professionals develop a better understanding of weed biology, non-chemical weed control tactics and herbicide-resistance, to help develop effective and more robust weed management programs for the long-term. Results - In an evaluation of the event, 98% agreed that they "have situations in which I can use what I have learned at this program" and 90% agreed that "I will change at least one of my practices based on what I learned from this program." On average, there was an increase in committing to specific practices from before to after the workshop. The greatest increases were shown in: use more than 1 effective herbicide to control key weed species (62%), use more than 1 HR crop technology and/or conv. herbicide program in my weed management program (58%), include planting date as a consideration in my weed management program (43%), and utilize mechanical and/or cultural control tactics for weed control (41%). Of the people attending the workshop, 76% were crop producers with 453,921 total acres. Of the participants were not a crop producer OR were ALSO an ag professional, consultant, etc., 21% of respondents managed or provided advice for 20,001 or more acres.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Goplen, J. J., C. C. Sheaffer, R. L. Becker, R. D. Moon, J. A. Coulter, F. R. Breitenbach, L. M. Behnken, and J. L. Gunsolus. 2017. Giant ragweed (Ambrosia trifida) emergence model performance evaluated in diverse cropping systems. Weed Science. 66:36-46.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Goplen, J.J., J.A. Coulter, C.C. Sheaffer, R.L. Becker, F.R. Breitenbach, L.M. Behnken, and J.L. Gunsolus. 2017. Economic performance of crop rotations in the presence of herbicide-resistant giant ragweed. Agronomy Journal. 110:260-268.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Goplen, J. J., C. C. Sheaffer, R. L. Becker, J. A. Coulter, F. R. Breitenbach, L. M. Behnken, and J. L. Gunsolus. 2018. Giant ragweed emergence pattern influenced by spring tillage timing in Minnesota. Crop, Forage and Turfgrass Management. doi: 10.2134/cftm2018.04.0025.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Norsworthy, J.K., M. Owen, J. Gunsolus, W.J. Everman, D.E. Ervin, G. Frisvold, T. Hurley, R. Jussaume, S. Welcher. 2017. A survey of BMP adoption for resistance management in U.S. row crops. Weed Science Soc. of America Abstracts. 45:252.
http://wssaabstracts.com/public/45/proceedings.html
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Frisvold, G., D.E. Ervin, W.J. Everman, J. Gunsolus, T. Hurley, R. Jussaume, J.K. Norsworthy, M. Owen, K. Dentzman. 2017. Socio-economic factors affecting farmer use of weed best management practices. Weed Science Soc. of America Abstracts. 45:254.
http://wssaabstracts.com/public/45/proceedings.html
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2017
Citation:
Owen, M.D., W.J. Everman, J. Gunsolus, J.K. Norsworthy, K. Dentzman, G. Frisvold, R. Jussaume, T. Hurley, S. Wechsler. 2017. Farmer perspectives and expectations: what is thought about herbicide-resistant weed management? Weed Science Soc. of America Abstracts. 45:269.
http://wssaabstracts.com/public/45/proceedings.html
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Ervin, D.E., K. Dentzman, W.J. Everman, G. Frisvold, J. Gunsolus, R. Jussaume, J.K. Norsworthy, T. Hurley, M. Owen, S. Wechsler. 2017. Neighbor and community effects of herbicide resistance management: a national survey of farm operators. Weed Science Soc. of America Abstracts. 45:271. http://wssaabstracts.com/public/45/proceedings.html
|
Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Accomplishments of my 2016 activities toward proactive and reactive approaches to herbicide-resistant weed management are divided by audience and are noted as follows: Farmer audience Awareness of the impact and need for prevention of herbicide-resistant weed species continues to grow. Information and education on addressing herbicide resistance and tactics to increase chemical and cultural diversification are in greater demand and data generated in cooperation with the agrichemical industry is available at our Applied Weed Science Web Site at http://appliedweeds.cfans.umn.edu/ and management strategies and tactics are available at the Extension Web Site: http://www.extension.umn.edu/agriculture/crops/ I was involved in ten farmer-events to discuss some of the work that I have been doing with the Weed Management Team at these locations (attendance across locations totaled ~500). Four of these events were devoted to in-depth education using in-field research and demonstration field trials to assist farmers and those who influence farmers (retail dealers and the agricultural press) in making weed management decisions based on weed biology, ecology and agronomics. I am also working on a NIFA grant surveying herbicide resistance attitudes and management practices of farmers. Our team of weed scientists, sociologists and economists are just beginning to investigate the results of our listening sessions and a national survey and some findings are just beginning to be published. I was involved in establishing two farmer listening sessions in MN that were facilitated by a sociologist and I contributed to the nation-wide survey instrument. Focus group results from a diverse set of states show that farmers are reluctant to discuss a neighbor's poor weed management practices with that neighbor and one lesson for extension efforts is that lack of awareness is not an adoption barrier, while time constraints, faith in new technologies, and reticence to tell others "how to farm" are more important constraints. Advisors to farmers Crop advisors are a critical connection to farmers. I was an instructor at five of the six Ag Professional Update Sessions held in: Kasson, Lamberton, Morris, Waseca and Willmar, MN (attendance at the five sessions was 345). There were 254 who responded to our survey question regarding their specific clientele base, on average each ag. professional had 52 clients and influenced 57,470 acres. When extrapolated to all paid attendees there is a potential impact of 14.5 million acres across the state and surrounding regions. I established the curriculum and served as lead instructor at the Ag Professional Field School, a two-day event held this summer on the Saint Paul campus. I was responsible for developing hands-on field plots and curriculum for two sessions that focused on "The Principles and Symptomology of Herbicide Mode of Action (HMOA)" and "Enlist and Xtend soybean response to various herbicides" The field-school effort is very time intensive during a very busy time of the year. The educational activities on day 1 were four in-depth 1.5-hour sessions repeated 4 times so all participants were involved in each session - this included the HMOA session. Attendance at my sessions was 121 for day 1 and 60 out of a potential 120 attendees for day 2. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The approach to diversification of herbicide-based weed management systems is now being explored via researching the barriers to adoption of herbicide resistant weed management practices. I will continue my research and education efforts in this critical area by addressing the interaction of weed biology, ecology and agronomics with the interaction of economics and sociological factors. I am part of a NIFA team of weed scientists, sociologists and economists who are just beginning to investigate the results of our listening sessions and a national survey and some findings are just beginning to be published. USDA-AFRI Grant number 122422. I was involved in establishing two farmer listening sessions in MN that were facilitated by a sociologist and I contributed to the nation-wide survey instrument. Focus group results from a diverse set of states show that farmers are reluctant to discuss a neighbor's poor weed management practices with that neighbor and one lesson for extension efforts is that lack of awareness is not an adoption barrier, while time constraints, faith in new technologies, and reticence to tell others "how to farm" are more important constraints. Although not named as an author ote the reference in the article to "Data Sources from an Interdisciplinary Study on Weed Resistance" at: http://www.choicesmagazine.org/choices-magazine/theme-articles/herbicide/theme-overview-herbicide-resistance-management#sthash.TSDC5Y74.dpuf The graduate student research focused on the importance of cropping systems impact on depleting weed reserves continues to be published (see Goplen, et al. 2016 and 2017). Three significant findings regarding managing giant ragweed (Ambrosia trifida ) that is resistant to multiple herbicide sites of action are: If you prevent prevent giant ragweed from going to seed in your field for 2 years, the weed seed bank will be depleted by ~95%% of the initial population. There are fewer weed escapes in alfalfa and wheat than in corn and soybean with fewer giant ragweed emerging in these crops than in corn and soybean. Also, delaying planting or tillage dates can destroy early emerging giant ragweed and still produce good soybean yields because 95% of the giant ragweed population emerges by early June. In all crops, giant ragweed retains it's seed well into mid-October, with only ~30% shattering to the ground. Thus allowing an extended time period of weed removal or destruction via modified harvest equipment.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2016
Citation:
Stahl, L.A.B., L.M. Behnken, F.R. Breitenbach, R.P. Miller, D.Nicolai, J.L. Gunsolus. 2016. Use of an integrated pest management assessment as an educational, needs assessment and evaluation tool through TurningPoint. Journal of Extension [On-line], 54(5) Article 5FEA4.
Goplen, J. J., C. C. Sheaffer, R. L. Becker, J. A. Coulter, F. R. Breitenbach, L. M. Behnken, G. A. Johnson, J. L. Gunsolus. 2017. Seed bank depletion and emergence patterns of giant ragweed (Ambrosia trifida) in Minnesota cropping systems. Accepted in Weed Sci. http://dx.doi.org/10.1614/WS-D-16-00084.1
Gunsolus, J.L. 2015. Herbicide-resistant weeds: reliance on herbicide technologies alone wont manage the problem. In Proc. Crop Pest Management Short Course. [http://www.extension.umn.edu/agriculture/ag-professionals/cpm/2015/]
|
Progress 10/01/14 to 09/30/15
Outputs
Target Audience:This project targets two primary audiences, Minnesota farmers who produce corn and soybean and the crop consultants who advise them. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The research efforts on giant ragweed provided my graduated student extension education experience and professional experience by presenting at the North Central Weed Science Society and American Society of Agronomy meetings. How have the results been disseminated to communities of interest?Results have been disseminated via presentations at professional societieys, extension-based programming and web based outlets. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Accomplishments of my 2015 activities toward herbicide diversification and earlier timing of weed control are divided by audience and are noted as follows: Farmer audience Awareness of the impact and need for prevention of herbicide-resistant weed species continues to grow. Information and education on addressing herbicide resistance and tactics to increase chemical and cultural diversification are in greater demand and data generated in cooperation with the agrichemical industry is available at our Applied Weed Science Web Site at http://appliedweeds.cfans.umn.edu/ I was involved in three summer field days at Crookston, Waseca and Rochester to discuss some of the work that I have been doing with the Weed Management Team at these locations (attendance across locations totaled 340). I also expanded my summer programming audience by participating in three Advanced Weed Science Days at Lamberton, Rochester and Waseca (attendance across locations totaled 125). These three days were devoted to in-depth education using in-field research and demonstration field trials to assist farmers and those who influence farmers (retail dealers and the agricultural press) in making weed management decisions based on weed biology, ecology and agronomics. I am also working on a NIFA grant surveying herbicide resistance attitudes and management practices of farmers. Advisors to farmers Crop advisors are a critical connection to farmers. I was an instructor at five of the six Ag Professional Update Sessions held in: Kasson, Lamberton, Morris, Waseca and Willmar, MN (attendance at the five sessions was 312). There were 312 who responded to our survey question regarding their specific clientele base, on average each ag. professional had 58 clients and influenced 60,472 acres for a potential impact of 3.5 million acres across the state and surrounding regions. I established the curriculum and served as lead instructor at the Ag Professional Field School, a two-day event held this summer on the Saint Paul campus. I was responsible for developing hands-on field plots and curriculum for two sessions that focused on "The Principles and Symptomology of Herbicide Mode of Action (HMOA)" and "Herbicide off-target crop injury potential." The field-school effort is very time intensive during a very busy time of the year. The educational activities on day 1 were four in-depth 1.5-hour sessions repeated 4 times so all participants were involved in each session - this included the HMOA session. To improve understanding of the HMOA plots an online session using our HMOA YouTube videos (https://www.youtube.com/watch?v=iAzz1EfYiDc ) was developed to set-up a flipped classroom. Two-thirds of the participants used the videos and of the 53 attendees responding to our post-session survey they found this approach to be useful and 91% found this approach enhanced their learning the day of the session. On day 2, ten 50-minute sessions were repeated 3 times so any participant could attend six different sessions - this included the "herbicide off-target injury" session. All sessions are designed to be "hands on" and to simulate "in field" conditions. Attendance at my sessions was 125 for day 1 and 60 out of a potential 120 attendees for day 2. The accomplishments of my 2015 activities toward the impact of preventing weed seed production and the depletion of weed seed reserves are noted as follows: Giant Ragweed (Ambrosia trifida) Seed Production and Retention in Soybean and Field Margins The objective of this research was to monitor seed rain of giant ragweed to determine when giant ragweed naturally drops its seed in both soybean and in adjacent field margins. The results of this research have been accepted for publication in Weed Technology in 2016. The findings indicate that giant ragweed retains its seed well into the fall with only 30% of the seeds shattering by our average MN soybean harvest date of October 15. These results suggest that alternative weed management practices that capture or destroy giant ragweed seed at crop harvest have potential for being used in a giant ragweed management strategy, by limiting the replenishment of the seed-bank. These results also indicate that mowing fence-lines surrounding crop production fields can also effectively reduce inputs into the weed seed bank. Seed-Bank depletion of giant ragweed (Ambrosia trifida) in various crop rotations This research includes two replicated field experiments, established in 2012 and 2013 near Rochester, MN, to monitor giant ragweed seed-bank depletion in different crops and crop rotations. The objective of this research was to determine how six different three-year crop rotationsaffect giant ragweed seed-bank depletion, and ultimately determine the most appropriate combination of crops to manage glyphosate- and ALS- resistant giant ragweed. The crop rotations contain corn (C), soybean (S), alfalfa (A), and wheat (W) in the following arrangements: CCC, SCC, CSC, SWC, SAC, AAC. Results from this research will be submitted for publication in 2016 and the findings indicate that maintaining a zero tolerance for inputs into the weed seed bank for two years can decrease giant ragweed populations by ~95% regardless of crop rotation. Also, regardless of cropping system, 95% of the giant ragweed population that germinated in any year emerged by June 9. Giant ragweed emergence numbers were reduced when alfalfa or wheat were in the rotation due to greater crop competition and crop harvest schedules that limited seed production potential. The low level of emergence in wheat, seedling alfalfa, and established alfalfa is likely due to early season soil conditions being less conducive to giant ragweed emergence. Established alfalfa also provides conditions more favorable for seed degradation by seed predators and soil microorganisms. These results show that herbicide-resistant giant ragweed infested fields can be managed by utilizing various crop rotations in addition to strategic timings of mechanical and chemical weed control options, which can be part of an integrated weed management plan directly targeting early emerging weeds.
Publications
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2016
Citation:
Goplen, J., C. C. Sheaffer, R. L. Becker, J. A. Coulter, F. R. Breitenbach, L. M. Behnken, G. A. Johnson, J. L. Gunsolus. 2016. Giant ragweed (Ambrosia trifida) seed production and retention in soybean and field margins. Weed Tech. (accepted for publication on October 4, 2015)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Gunsolus, J.L. 2014. Addressing several barriers to diversification of weed management by revealing the hidden costs of biological time constraints. Proc. North Centr. Weed Sci. Soc. 69:197.
http://ncwss.org/wp-content/uploads/2015/03/NCWSS-2014-Proceedings.pdf
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Gunsolus, J.L. 2015. Removing barriers to weed management diversification by highlighting the hidden costs of biological time constraints. 8th International IPM Symposium (33.4)
http://www.ipmcenters.org/ipmsymposium15/Documents/IPM_2015_Proceedings-final.pdf
|
Progress 10/01/13 to 09/30/14
Outputs
Target Audience: This project targets two primary audiences, Minnesota farmers who produce corn and soybean and the crop consultants who advise them. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The research efforts on giant ragweed seed retention and deplition have provided my graduate student extension education experience and his preliminary results concerning this research have already reached a wide audience. The research was presented at the December North Central Weed Science Society and American Society of Agronomy meetings. Posters have also been presented at both the Production Agriculture and Plant Breeding Symposiums at the University of Minnesota in Saint Paul, MN and the research has also been used in numerous extension programs, including the Rochester Field Day and various winter workshops. Additionally, this research will be integrated into Extension programming sessions which will convey the research and recommendations to professionals who advise many of Minnesota’s farmers. How have the results been disseminated to communities of interest? Results have been disseminated via presentations at professional societies (e.g. North Central Weed Science Society and American Society of Agronomy), Extension-based programs (e.g. Crop Pest Management Short Course and Ag Professional Update series) and web-based outlets such as http://appliedweeds.cfans.umn.edu/ and http://www.extension.umn.edu/agriculture/crops/ Awareness of the herbicide-resistant weedss issue has also expanded to the broader public sector. In January of 2014 Dr. Don Wyse and I were asked to present at an informational legislative hearing on herbicide-resistant weeds. I also served as a key informational source for a Minneapolis StarTribune newspaper article on herbicide resistant weeds. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Accomplishments of my 2014 activities toward herbicide diversification and earlier timing of weed control are divided by audience and are noted as follows: Farmer audience Awareness of the impact and need for prevention of herbicide-resistant weed species is growing in the farming community.Due to the urgency of the herbicide resistance management message I took on a significant amount of producer-focused winter programming this year. I presented at 11 meetings to a total of 1085 crop producers. Due to the absence of a sugar beet weed scientist this includes one sugar beet producer meeting where I spoke to 250 people. I was involved in three summer field days (attendance across locations totaled 150). I also expanded my summer programming audience by addressing the 15 board members of the Catholic Rural Life organization and I spoke to 50 farmers and their bankers at the Independent Community Bankers of MN and the Upper Midwest Agricultural Credit Council Ag Conference in Worthington, MN. Awareness of this issue has also expanded to the broader public sector. In January of 2014 Dr. Don Wyse and I were asked to present at an informational legislative hearing on herbicide-resistant weeds. I also served as a key informational source for a Minneapolis StarTribune newspaper article on herbicide resistant weeds. Advisors to farmers Crop advisors are a vital connection to farmers. To illustrate, I was an instructor at five Ag Professional Update sessions held in: five locations across MN (attendance at the five sessions was 340). There were 195 who responded to our survey question regarding their specific clientele base, on average each Ag. professional had 46 clients and influenced 46,150 acres for a potential impact of 4.0 million acres across the state and surrounding regions. The Crop Pest Management (CPM)Short Course program has a similar impact on the farming community. In December I presented at the CPM Short Course on “Now that the weeds have our attention: Lessons to be learned” and attendance for my presentation was 100. In the summer Iserved as Discipline Leader for the Ag Professional Field School, a two-day event held on the Saint Paul campus and I was responsible for developing hands-on field plots and curriculum for two sessions that focused on “The Principles and Symptomology of Herbicide Mode of Action (HMOA)” and “Preemergence Herbicide Strategies in Soybean.” The educational activities on day 1 were four in-depth 1.5-hour sessions repeated 4 times so all participants were involved in each session - this included the HMOA session. On day 2, ten 50-minute sessions were repeated 3 times so any participant could attend six different sessions – this included the “Preemergence Herbicide Strategies in Soybean" session. All sessions are designed to be “hands on” and to simulate “in field” conditions. Attendance at my sessions was 115 for day 1 and 60 out of a potential 115 attendees for day 2. The Field School is a valued learning event due to the hands-on approach and instructor interaction; Average learning gain for the day one session was 1.2 on a 1=initially knew very little to 5= initially knew a lot before the session started. This session also incorporated video (https://www.youtube.com/user/UMNCrops ) to create a “flipped classroom” teaching opportunity which was well received. The accomplishments of my 2014 activities toward the impact of preventing weed seed production and the depletion of weed seed reserves are noted as follows: Giant Ragweed (Ambrosia trifida) Seed Production and Retention in Soybean and Field Margins The objective of this research was to monitor seed rain of giant ragweed to determine when giant ragweed naturally drops its seed in both soybean and in adjacent field margins. Seed was collected each week using seed collection traps through September and October in 2012 to 2014 in Rosemount, MN. These results will be useful in determining the potential to use various nonchemical and integrated methods of late-season weed control targeting weed seed production and spread. Giant ragweed plants produced an average of 1796 ± 413 seeds per plant in 2012, with only 64% ± 4% of the seed being potentially viable. In 2013, giant ragweed plants produced 1115 ± 414 seeds per plant, with 76.5% ± 3% of the seed being potentially viable Giant ragweed began naturally dropping seed the first week of September and continued through October in both 2012 and 2013. Much of the seed remained on the plant well into the fall, with 80% ± 4% and 47% ± 4% of the potentially viable seed remaining on the plant at the end of October in 2012 and 2013, respectively, which is after the typical harvest date for soybean These results suggest that alternative weed management practices that capture or destroy giant ragweed seed at crop harvest have potential for being used in a giant ragweed management strategy, by limiting the replenishment of the seed-bank. However, the effectiveness may be highly variable among years as was seen between 2012 and 2013. Seed-Bank depletion of giant ragweed (Ambrosia trifida) in various crop rotations This research includes two replicated field experiments, established in 2012 and 2013 near Rochester, MN, to monitor giant ragweed seed-bank depletion in different crops and crop rotations. The objective of this research was to determine how six different three-year crop rotationsaffect giant ragweed seed-bank depletion, and ultimately determine the most appropriate combination of crops to manage glyphosate- and ALS- resistant giant ragweed. The crop rotations contain corn (C), soybean (S), alfalfa (A), and wheat (W) in the following arrangements: CCC, SCC, CSC, SWC, SAC, AAC. The progress made regarding the seed-bank depletion portion of this research has included characterizing the initial seed-bank density of giant ragweed at the first field site. Soil seed-bank samples were taken the summer of 2012, were wet sieved, and seed was extracted before counting the total number of intact giant ragweed seeds in each soil sample to determine the giant ragweed seed-bank density. The starting seed-bank densities were highly variable throughout the experimental location, with seed densities at specific sampling quadrats ranging from 0 to 319 seeds/m2. To study seed-bank depletion over the course of the study, all emerged giant ragweed was eliminated to prevent seed input into the seed bank. Giant ragweed emergence was highly variable among years due to the overall depletion in the seed bank over time and the influence of variable soil temperature and moisture, with 11.4, 58.4, and 3.9 seedlings m-2yr-1 emerging in 2012, 2013, and 2014, respectively. Across all treatments in 2013, 94.8% of the total giant ragweed emerged by June 3rd, while 82.6% emerged by the same date in 2014. Wheat and alfalfa, which were established early in the growing season in 2013, had lower giant ragweed emergence than later-planted corn and soybean. Cumulative giant ragweed populations in 2013 were 93.3, 61.5, 42.7, 39.8, and 19.7 seedlings m-2 in corn, soybean, wheat, seedling alfalfa, and established alfalfa, respectfully. The low level of emergence in wheat, seedling alfalfa, and established alfalfa is likely due to early season soil conditions being less conducive to giant ragweed emergence. Established alfalfa also provides conditions more favorable for seed degradation by seed predators and soil microorganisms. These results show that herbicide-resistant giant ragweed infested fields can be managed by utilizing various crop rotations in addition to strategic timings of mechanical and chemical weed control options, which can be part of an integrated weed management plan directly targeting early emerging weeds
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Behnken, L.M., F. Breitenbach, J.L. Gunsolus, R.M. Miller. 2013. Time of weed removal in corn and soybeans, a field teaching tool seeing is believing. Proc. North Centr. Weed Sci. Soc. 68:39. http://www.ncwss.org/proceed/NCWSS-2013-Proceedings.pdf
Goplen, J.J., J.L. Gunsolus, C. Sheaffer, R. Becker, J. Coulter, F. Breitenbach, L.M. Behnken, G. Johnson. 2013. Giant ragweed seed production and retention in soybean and field margins. Proc. North Centr. Weed Sci. Soc. 68:116. http://www.ncwss.org/proceed/NCWSS-2013-Proceedings.pdf
Gunsolus, J.L. 2013. Now that the weeds have our attention: Lessons to be learned. In Proc. Crop Pest Management Short Course. [http://www.extension.umn.edu/agriculture/ag-professionals/cpm/2013/index.html]
|
Progress 01/01/13 to 09/30/13
Outputs
Target Audience: This project targets two primary audiences, Minnesota farmers who produce corn and soybean and the crop consultants who advise them. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? I and several of the cooperating personnel (F. Breitenbach and L. Behnken) regularly attended the North Central Weed Science Society meetings; Dec. 10-13, 2012 in St. Louis, MO and Dec. 9-12, 2013 in Columbus, OH. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The accomplishments of my activities in 2013 toward my first objective are divided by audience - farmers and advisors to farmers. As the need grows for greater awareness by Minnesota corn and soybean farmers of the impact and prevention of glyphosate resistant weed species on their farming operation, the positive results of my applied research and educational programming efforts is apparent. Information and education on implementing herbicide combinations with and alternatives to glyphosate are in greater demand as reflected by continued grant-in-aid support from the agrichemical industryand the data generated in cooperation with the agrichemical industry is available at our Applied Weed Science Web Site: http://appliedweeds.cfans.umn.edu/. This year Pioneer Hi-Bred and the MN Soybean Research & Promotion Council (MNSR&PC) saw the need for more in-depth farmer education on managing resistant weeds. In February I discussed herbicide-resistant weed management to ~150 farmers at a Pioneer general session held in Windom, MN. In March 2013 the MSR&PC requested my involvement on the herbicide-resistant weed issue at two different venues: 1) The Soybean Symposium held at the Landscape Arboretum. 2) A three city, seminar series (Productivity Optimization Dialog Seminars or PODS) in Mahnomen, Willmar, and Mankato focused on Weed Resistance. The meeting reached ~250 farmers across the three locations. The MN Soybean Growers Association felt these events were successful in connecting farmers, researchers, and industry to learn about this important issue. I was involved in three summer field days at Morris, Lamberton and Rochester to discuss some of the work that I have been doing with the Weed Management Team at these locations (attendance across locations totaled 150). Improving extension’s communication with farmers and the people who consult with farmers is an on-going process. In 2012/2013 contributions to the Minnesota Crop News blog (consultant focused with 1,600 subscribers at http://blog.lib.umn.edu/efans/cropnews/ ) is now coordinated with the U of MN Extensions Ag News Wire (farmer/local, regional and national news focused at: http://blog.lib.umn.edu/umnext/news/ag-news-wire/ ). My focus on information disseminators, the advisors to farmers, focused on short courses, an annual update series and a two-day Field School. In 2012/2013 I served on the Evaluation and Planning Committee to develop the Crop Pest Management Short Course program and the presenton “Integrating Residual Herbicides into Corn and Soybean Weed Management Plans”). Attendance for my presentation was 105. I was an instructor at five Ag Professional Update Sessions(attendance at the five sessions was 387). There were 184 who responded to our survey question regarding their specific clientele base, this program’s multiplier effect extended to 4180 clients and 3.2 million acres served. I served on the Planning Committee and as a Discipline Leader for the Ag Professional Field School, a two-day event held this summer on the Saint Paul campus. As Discipline Leader I was responsible for developing hands-on field plots and curriculum for two sessions that focused on “The Principles and Symptomology of Herbicide Mode of Action (HMOA)” (four, 1.5 hour sessions) and “Preemergence Herbicide Strategies in Soybean.” (three, 50 minute sessions). All sessions are designed to be “hands on” and to simulate “in field” conditions. Attendance at my sessions was 125 for day 1 and 119 out of a potential 122 attendees for day 2. The accomplishments of my activities in 2013 toward my second objective involve serving on one M.S. thesis committee and co-adivisng another student persuing a M.S. degree. The completed M.S. thesis focused on comparing chemical and non-chemical based weed management systems in soybean, including the use of winter rye and field pennycress as cover crops. The current M.S. student is investigating crop rotation strategies for the management of herbicide-resistant giant ragweed. This research is investigating the impact of various cropping systems on the rate and duration of weed emergence, impact on the weed seedbank and the amount of seed production and retention.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Flipp, A.M., G. Johnson, J. Gunsolus, D. Wyse. 2012. Integrated weed management using row spacing, cover crops, and soybean varieties. Proc. North Centr. Weed Sci. Soc. 67:104. http://www.ncwss.org/proceed/NCWSS-2012-Proceedings.pdf
- Type:
Theses/Dissertations
Status:
Submitted
Year Published:
2013
Citation:
Flipp, A. M. 2013. Integrated weed management in soybean. M. S. Thesis.
University of Minnesota.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: The development of glyphosate-resistant alfalfa, cotton, corn, soybean and sugarbeet cultivars has led to glyphosate's status as the most widely-used herbicide. However, application to large weeds and repeated use of glyphosate also has led to an increase in glyphosate-resistant weed biotypes. Concurrently, the frequency of weed biotypes exhibiting herbicide resistance to multiple mechanisms of action is increasing as well. As multiple-resistance weed biotypes become more frequent and weed seed bank densities increase, the efficacy of existing and developing herbicide-resistant crop technologies decline, with decreased profitability. Research and education activities were specifically directed toward the adoption of integrated weed management practices for the proper use of glyphosate in Roundup Ready Corn and Soybean technology, focusing on economics and mitigating weed species shifts due to herbicide resistance. A coupling of research findings with an economic analysis of sequential preemergence and postemergence herbicide-based weed management systems indicates a projected trend for more soil-applied herbicides to be used in conjunction with glyphosate in glyphosate-resistant crops. Results have been disseminated via Commodity Crops and Institute for Ag Professionals (IAP) extension programming and incorporated into weed management recommendations published on the Applied Weed Science Research web site at http://appliedweeds.cfans.umn.edu/. In the winter of 2012, Pioneer Hi-Bred, West Central Co-op, and Winfield Solutions invited me to their winter training sessions to discuss management strategies that address herbicide-resistant weed management. This summer, in conjunction with several team members, we conducted an in-house "hands-on" field training session that was used extensively by several agribusiness companies' for in-field education about weed management principles. PARTICIPANTS: F.R. Breitenbach (CPM Specialist Rochester, MN), L. M. Behnken (Regional Extension Educator Rochester, MN), J.K. Getting (Southwest Research and Outreach Center), T.R. Hoverstad and G.A. Johnson (Southern Research and Outreach Center), D.W. Miller and B.D. Kinkaid (Dept. of Agronomy and Plant Genetics), Jeff Stachler (North Dakota State University). Opportunities for training and professional development provided by the project included participation in the Institute for Ag Professionals extension programming events held in January (Ag Professional Updates - 5 locations), July (Ag Professional Field School - one 2-day event with extensive hands-on training under field conditions) and the December (one 2-day Crop Pest Management Short Course). TARGET AUDIENCES: Crop consultants, seed and agrichemical dealers and other professionals who work with corn and soybean farmers were the target audience as they interact and are known at the local community level. Corn and soy bean farmers were directly targeted via U of MN Extension Ag News Wire and farm magazines. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost- effective integrated weed management programs that will be implemented by producers. Implementation will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from the development of herbicide resistant weeds. Currently, several weed species are resistant to glyphosate; Ambrosia trifida L., Ambrosia artemisifolia L. and Amaranthus rudis Sauer and are present in some soybean and corn fields. Therefore, the need for complimentary weed management tools to avoid significant changes in weed populations is critical. In 2010, MN had approximately 50% of the corn and <2% of the soybean acres treated with a preemergence, soil-residual herbicide. Due to the emergence of glyphosate resistance and the favorable economics and improvements in timeliness of glyphosate application when preemergence herbicides precede glyphosate application, an increase in the use of preemergence herbicides in MN corn and soybean cropping systems is necessary. Although the project is lacking official herbicide use statistics for MN, agrichemical industry contacts have reported a significant increase in the use of preemergence herbicide use in soybeans - estimated at 35% of 2012 soybean acres. Estimates of learning gains and practice changes taken during five IAP programs via an audience pre- and post- self-evaluation, using a scale of 1(very little) to 5 (very much), estimated learning gains for tactics to delay herbicide resistant weeds and reduce economic and agronomic risks associated with Roundup Ready Technology increased by 0.57 and anticipated practice changes for increased use of preemergence herbicides in soybean increased by 0.56. The audience evaluated estimated the number of acres potentially influenced by this programming effort (as a function of acres managed and attendance) to be ~ 721,000 acres.
Publications
- Gunsolus, J.L. and D.W. Miller. 2011. Soybean herbicide management with preemergence and postemergence applications of Zidua at Rosemount, MN-2011. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J.L., Breitenbach, F.R., L.M. Behnken, T. R. Hoverstad, J. K. Getting, G. Nelson, R. P. Miller. 2011 . Evaluation of weed management systems in corn and soybean. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J. L. 2011. First steps to taking control of herbicide-resistant weeds. MN Extension Crop News. Dec. 5 [blog.lib.umn.edu/efans/cropnews/].
- Gunsolus, J. L. 2011. Needed changes in corn and soybean weed management-adapting to changing weed populations. In Proc. Crop Pest Management Short Course. [http://www.extension.umn.edu/AgProfessionals/cpm2011proceedings.html ]
- Gunsolus, J.L. and D.W. Miller. 2011. Annual weed control with Fierce and other preemergence herbicides at Rosemount, MN-2011. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J.L. and D.W. Miller. 2011. Soybean herbicide management with preemergence and postemergence applications of Anthem at Rosemount, MN-2011. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J.L. and D.W. Miller. 2011. Soybean herbicide management with preemergence and postemergence applications of Warrant at Rosemount, MN-2011. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Variability inherent in agriculture influences weed management decisions. Farmers perceive variability associated with integrated weed management in terms of yield, economic returns, and time management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. Successful adoption requires crop producers to align their economic returns and time and labor management issues with existing biological time constraints. Research and education activities were specifically directed toward the adoption of integrated weed management practices for the proper use of glyphosate in Roundup Ready Corn and Soybean technology, focusing on economics and mitigating weed species shifts due to herbicide resistance. A coupling of research findings with an economic analysis of sequential preemergence and postemergence herbicide-based weed management systems indicates a projected trend for more soil-applied herbicides to be used in conjunction with glyphosate in glyphosate-resistant crops. Results have been disseminated via Commodity Crops and Institute for Ag Professionals (IAP) extension programming and incorporated into weed management recommendations published on the Applied Weed Science Research web site at http://appliedweeds.cfans.umn.edu/. A news release focused on proactive responses to glyphosate resistant weed development was sent to over 17,000 Roundup Ready licensees in MN and ND by Monsanto as a means of addressing the glyphosate resistant weeds issue. Project results were also disseminated via a U-tube video that was produced in cooperation with the Minnesota Soybean Research and Promotion Board at http://www.youtube.com/playlistlist=PLCE78C5645290E1DB. PARTICIPANTS: F.R. Breitenbach (CPM Specialist Rochester, MN), L. M. Behnken (Regional Extension Educator Rochester, MN), J.K. Getting (Southwest Research and Outreach Center), T.R. Hoverstad and G.A. Johnson (Southern Research and Outreach Center), D.W. Miller and B.D. Kinkaid (Dept. of Agronomy and Plant Genetics), Jeff Stachler and Richard Zollinger (North Dakota State University). Opportunities for training and professional development provided by the project included participation in the Institute for Ag Professionals extension programming events held in January (Ag Professional Updates - 5 locations), July (Ag Professional Field School - one 2-day event with extensive hands-on training under field conditions) and the December (one 2-day Crop Pest Management Short Course). TARGET AUDIENCES: Crop consultants, seed and agrichemical dealers and other professionals who work with corn and soybean farmers were the target audience as they interact and are known at the local community level. Corn and soy bean farmers were directly targeted via the U-tube video, U of MN Extension Ag News Wire and farm magazines. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost- effective integrated weed management programs that will be implemented by producers. Implementation will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from the development of herbicide resistant weeds. Currently, several weed species are resistant to glyphosate; Ambrosia trifida L., Ambrosia artemisifolia L. and Amaranthus rudis Sauer and are present in some soybean and corn fields. Therefore, the need for complimentary weed management tools to avoid significant changes in weed populations is critical. In 2010, MN had approximately 50% of the corn and <2% of the soybean acres treated with a preemergence, soil-residual herbicide. Due to the emergence of glyphosate resistance and the favorable economics and improvements in timeliness of glyphosate application when preemergence herbicides precede glyphosate application, an increase in the use of preemergence herbicides in MN corn and soybean cropping systems is necessary. Although the project is lacking official herbicide use statistics for MN, agrichemical industry contacts have reported a significant increase in the use of preemergence herbicide use in soybeans - estimated at 15% of 2011 soybean acres. Estimates of learning gains and practice changes taken during five IAP programs via an audience pre- and post- self-evaluation, using a scale of 1(very little) to 5 (very much), estimated learning gains for tactics to delay herbicide resistant weeds and reduce economic and agronomic risks associated with Roundup Ready Technology increased by 0.45 and anticipated practice changes for increased use of preemergence herbicides in corn and soybean increased by 0.26 and 0.48, respectively. The audience evaluated estimated the number of acres potentially influenced by this programming effort (as a function of acres managed and attendance) to be 1 million acres.
Publications
- Gunsolus, J., D. Wyse, K. Moncada and C. Fernholz. 2011. Weed Management. In Tools for Managing Pest and Environmental Risks to Organic Crops in the Upper Midwest. K. M. Moncada and C. C. Sheaffer (eds.). http://www.organicriskmanagement.umn.edu/introduction1.html
- Bernards, M.L., T.M. Dale, R.G. Hartzler, M.D. Owen, D. Peterson, D. E. Shoup. J.L. Gunsolus, S. Z. Knezevic, R. G. Wilson, R. Zollinger, M.J. Moechnig, D. Refsell, J. A. Pawlak. 2010. Residual activity of flumioxazin + pyroxasulfone in western soybean belt. Proc. North Centr. Weed Sci. Soc. 65:41. http://www.ncwss.org/proceed/NCWSS-2010-Proceedings.pdf
- Gunsolus, J.L. and D.W. Miller. 2010. Acetochlor and competitive weed control systems in Roundup-Ready corn at Rosemount, MN. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J.L. and D.W. Miller. 2010. Soybean herbicide management with MON 63410 at Rosemount, MN. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J.L. and D.W. Miller. 2010. Annual weed control with Fierce, Valor, Gangster, Authority Assist, Authority First, Optill, Prowl and Prefix at Rosemount, MN. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J.L., Breitenbach, F.R., L.M. Behnken, T. R. Hoverstad, J. K. Getting, G. Nelson, R. P. Miller. 2010 .Evaluation of weed management systems in field corn. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J.L., Breitenbach, F.R., L.M. Behnken, T. R. Hoverstad, J. K. Getting, G. Nelson, R. P. Miller. 2010 .Evaluation of weed management systems in soybean. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J. L. and J. Stachler. 2010. PRE and POST herbicide diversification options for glyphosate-resistant corn and soybean. University of Minnesota Applied Weed Science Research web site publications; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J. L. 2011. New year, new options for weed management. In Farm & Ranch Guide. Posted Jan. 26, 2011 at [farmandranchguide.com]
- Gunsolus, J. L. 2011. Five tips for corn weed management - Start with a clean field and then control weeds early as they reach four inches. In Corn & Soybean Digest. Posted Feb. 9, 2011 at [cornandsoybeandigest.com]
- Gunsolus, J. L., J. Stachler and R. Zollinger. 2011 Proper management of waterhemp - Now is the time to take control. MN Extension Crop News. May 11. [blog.lib.umn.edu/efans/cropnews/].
- Gunsolus, J. L. 2011. Delayed planting, crop rotation keys to weed control in organic corn, soybeans. Ag News Wire, University of Minnesota Extension. June 6. [http://blog.lib.umn.edu/umnext/news/ag-news-wire/]
- Gunsolus, J. L. 2011. Weed Management. U-tube video produced byt eh MN Soybean Research and Promotion Council [http://www.youtube.com/watchv=Nf8NEDMVowU]
- Miller, D. W., J. L. Gunsolus, B. R. Durgan, and R. L. Becker. 2000-2010. Applied Weed Science web site: http://appliedweeds.cfans.umn.edu/
- Johnson, G. A., F. Breitenbach, L. Behnken, R. Miller, T. Hoverstad, and J. Gunsolus. (In Press). Comparison of Herbicide Tactics to Minimize Species Shifts and Selection Pressure in Glyphosate-Resistant Soybean. Weed Technol. (Accepted for Publication in 2011)
|
Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Variability inherent in agriculture influences weed management decisions. Farmers perceive variability associated with integrated weed management in terms of yield, economic returns, and time management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. Successful adoption requires crop producers to align their time and labor management issues with existing biological time constraints. Research and education activities were specifically directed toward the adoption of integrated weed management practices for the proper use of glyphosate in Roundup Ready Corn and Soybean technology, focusing on economics and mitigating weed species shifts due to herbicide resistance. A coupling of research findings with an economic analysis of sequential preemergence and postemergence herbicide-based weed management systems indicates a projected trend for more soil-applied herbicides to be used in conjunction with glyphosate in glyphosate-resistant crops. Results have been disseminated via Commodity Crops and Institute for Ag Professionals (IAP) extension programming and incorporated into weed management recommendations published on the Applied Weed Science Research web site at http://appliedweeds.cfans.umn.edu/. PARTICIPANTS: F.R. Breitenbach (CPM Specialist Rochester, MN), L. M. Behnken (Regional Extension Educator Rochester, MN), J.K. Getting (Southwest Research and Outreach Center), T.R. Hoverstad and G.A. Johnson (Southern Research and Outreach Center), D.W. Miller and B.D. Kinkaid (Dept. of Agronomy and Plant Genetics). Opportunities for training and professional development provided by the project included participation in the Institute for Ag Professionals extension programming events held in January (Ag Professional Updates - 6 locations), July (Ag Professional Field School - one 2-day event with extensive hands-on training under field conditions) and the December (one 2-day Crop Pest Management Short Course). TARGET AUDIENCES: Crop consultants, seed and agrichemical dealers and other professionals who work with corn and soybean farmers were the target audience as they interact and are known at the local community level. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost- effective integrated weed management programs that will be implemented by producers. Implementation will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from the development of herbicide resistant weeds. Currently, several weed species are resistant to glyphosate; Ambrosia trifida L., Ambrosia artemisifolia L. and Amaranthus rudis Sauer and are present in some soybean and corn fields. Therefore, the need for complimentary weed management tools to avoid significant changes in weed populations is critical. Currently MN has approximately 50% of the corn and <2% of the soybean acres treated with a preemergence, soil-residual herbicide. Due to the emergence of glyphosate resistance and the favorable economics and improvements in timeliness of glyphosate application when preemergence herbicides precede glyphosate application, an increase in the use of preemergence herbicides in MN corn and soybean cropping systems is necessary. Estimates of learning gains and practice changes taken during five IAP programs via an audience pre- and post- self-evaluation, using a scale of 1(very little) to 5 (very much), estimated learning gains for tactics to delay herbicide resistant weeds and reduce economic and agronomic risks associated with Roundup Ready Technology increased by 0.40 and anticipated practice changes for increased use of preemergence herbicides in corn and soybean increased by 0.32 and 0.60, respectively. The audience evaluated estimated the number of acres potentially influenced by this programming effort (as a function of acres managed and attendance) to be 5.5 million acres.
Publications
- Gunsolus, J. L. 2009. Hidden costs of untimely weed control - controlling weeds to improve nitrogen use efficiency. In Proc. Crop Pest Management Short Course. [www.extension.umn.edu/AgProfessionals/cpmshortcourse.html]
- Behnken, L. M., R. P. Miller, F. R. Breitenbach, and J. L. Gunsolus. 2009. Comparison of preemergence and postemergence herbicide programs utilizing best management practice rates of atrazine or atrazine replacements in field corn at Rochester, MN. Proc. North Centr. Weed Sci. Soc. 64:36. [CD-ROM Computer File]. North Central Weed Sci. Soc., Champaign, IL.
- Behnken L. M.,Miller, R. P., F. R. Breitenbach, and J. L. Gunsolus. 2009. Utilization of sequential herbicide applications and tank mix components to improve glyphosate efficacy. Proc. North Centr. Weed Sci. Soc. 64:35. [CD-ROM Computer File]. North Central Weed Sci. Soc., Champaign, IL.
- Miller, R. P., F. R. Breitenbach, L. M. Behnken, J. L. Gunsolus, L. E. Kuisle, and S. A. Stellpflug. 2009. Evaluation of weed control strategies for Roundup Ready soybean in a hypothetical glyphosate resistant weed situation in soybean at Rochester, MN, in 2007, 2008 and 2009. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Breitenbach, F. R., L.M. Behnken, R. P Miller, J.L. Gunsolus, and J. Welter. 2009. Performance of Ignite 280 herbicide systems for weed control in soybean at Rochester, MN in 2009. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J. L. 2010. Control of volunteer soybean in corn. MN Extension Crop News. June 3. [blog.lib.umn.edu/efans/cropnews/].
- Gunsolus, J. L. 2010. Now is the time to finalize postemergence weed control in soybean. MN Extension Crop News. July 1. [blog.lib.umn.edu/efans/cropnews/].
- Gunsolus, J. L. 2010. Conditions are right for fall dandelion control in corn and soybean. MN Extension Crop News. October 15. [blog.lib.umn.edu/efans/cropnews/].
- Gunsolus, J. L. 2010. Diversify weed control strategies to keep glyphosate effective. Ag News Wire, University of Minnesota Extension. September 13. [http://www.extension.umn.edu/extensionnews/2010/glyphosate-resistanc e-strategies.html]
- Miller, D. W., J. L. Gunsolus, B. R. Durgan, and R. L. Becker. 2000-2010. Applied Weed Science web site: http://appliedweeds.cfans.umn.edu/
- Hoverstad, T. R., J. L. Gunsolus, F. R. Breitenbach, L. M. Behnken, R. P. Miller, J. K. Getting. 2009. Corn and Soybean herbicide economic evaluation trials over seven locations. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Behnken, L. M., F. R. Breitenbach, R. P. Miller, J. L. Gunsolus, A. D. Gehling, and K. M. Sheehan. 2009. Comparison of the impact of BMP rates of atrazine tank mixed with several broadleaf herbicides in field corn at Rochester, MN, in 2007, 2008 and 2009. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.htm
- Getting, J. K., L. M. Behnken, F. R. Breitenbach, J. L. Gunsolus, T. R. Hoverstad, and R. P. Miller. 2009. Evaluation of BMP rates of atrazine tank-mixed with broadleaf herbicides at Lamberton, MN in 2009. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.htm
|
Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. Studies conducted from 2004-2006 to better define corn and soybean sensitivity to early season weed competition indicate that corn yield is more likely to be reduced as a result of early season weed competition than is soybean. Coupling this research with an economic analysis of sequential preemergence and postemergence herbicide-based weed management systems, the projected trend is for more soil-applied herbicides to be used in conjunction with glyphosate in glyphosate-resistant crops. Results have been disseminated via Commodity Crops and Institute for Ag Professionals extension programming and incorporated into weed management recommendations published on the Applied Weed Science Research web site at http://appliedweeds.cfans.umn.edu/ PARTICIPANTS: F.R. Breitenbach (CPM Specialist Rochester, MN), L. M. Behnken (Regional Extension Educator Rochester, MN), J.K. Getting (Southwest Research and Outreach Center), T.R. Hoverstad and G.A. Johnson (Southern Research and Outreach Center), D.W. Miller and B.D. Kinkaid (Dept. of Agronomy and Plant Genetics). Opportunities for training and professional development provided by the project included participation in the Institute for Ag Professionals extension programming events held in January (Ag Professional Updates - 7 locations), July (Ag Professional Field School - one 2-day event with extensive hands-on training under field conditions) and the December (on 2-day Crop Pest Management Short Course). TARGET AUDIENCES: Crop consultants, seed and agrichemical dealers and other professionals who work with corn and soybean farmers were the target audience as they interact and are known at the local community level. PROJECT MODIFICATIONS: No significant changes over this reporting period.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost-effective integrated weed management programs that will be implemented by producers. Implementation of integrated weed management programs will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from weed species shifts and the development of herbicide resistant weeds. Research results identified several weed species (Ambrosia trifida L., Ambrosia artemisifolia L. and Amaranthus rudis Sauer) that are present in some soybean and corn fields that are resistant to 4 to 8 times the label use rate of glyphosate in glyphosate-resistant crops and suggests the need for complimentary weed management tools to avoid significant changes in weed populations. Currently MN has approximately 50% of the corn and <2% of the soybean acres treated with a preemergence, soil-residual herbicide. Due to the emergence of glyphosate resistance and the favorable economics and improvements in timeliness of glyphosate application when preemergence herbicides precede glyphosate application, look for an increase in the use of preemergence herbicides in MN corn and soybean cropping systems.
Publications
- Behnken, L.M., Breitenbach, F. R., Miller, R.P., Hoverstad, T.R., Getting, J.K. and Gunsolus, J.L. 2008.Weed Management in field corn at Rochester, MN, in 2008. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Miller, R. P., Breitenbach , F.R., Behnken, L.M., Gunsolus, J.L., Kuisle, L.E., and Stellpflug, S.A. 2008. Evaluation of weed control strategies for Roundup Ready soybean in a hypothetical glyphosate resistant weed situation in soybean at Rochester, MN, in 2007 and 2008. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Getting, J.K., Gunsolus, J.L., and Hoverstad, T.R. 2008. Herbicide performance in soybeans at Lamberton, MN in 2008. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Miller, R.P., Breitenbach, F.R., Behnken, L.M., Hoverstad, T.R., Getting, J.K. and Gunsolus, J.L. 2008. Weed Management in soybean at Rochester, MN, in 2008. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
- Gunsolus, J. L. 2009. Glyphosate nonperformance issues and glyphosate-resistant biotypes. In Corn & Soybean Digest at [cornandsoybeandigest.com/corn/news]. June 16, 2009.
- Gunsolus, J. L. 2009. Glyphosate nonperformance issues and glyphosate-resistant biotypes. MN Extension Crop News. June 12. [blog.lib.umn.edu/efans/cropnews/]
- Gunsolus, J.L. 2009. Best management practices in a world of risks and constraints. Weed Sci. Soc. Am. Abstract 449. [Web file wssa.net/Meetings/WSSAAbstracts/abstractsearch.php]
- Gunsolus, J.L. 2008. Glyphosate management strategies to reduce risk in corn/soybean cropping systems. In Proc. Crop Pest Management Short Course [www.extension.umn.edu/AgProfessionals/cpmshortcourse.html]
- Miller, R.P., Behnken, L.M., Breitenbach, F.R., and Gunsolus, J.L. 2008. Utilization of sequential herbicide applications and tank mix components to improve glyphosate efficacy. Proc. North Centr. Weed Sci. Soc. 63:40. [CD-ROM Computer File]. North Central Weed Sci. Soc., Champaign, IL.
- Getting, J.K., Gunsolus, J.L., and Hoverstad, T.R. 2008. Herbicide performance in corn at Lamberton, MN in 2008. University of Minnesota Applied Weed Science Research web site research report; appliedweeds.cfans.umn.edu/index.html
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. Studies conducted from 2004-2006 to better define corn and soybean sensitivity to early season weed competition indicate that corn yield is more likely to be reduced as a result of early season weed competition than is soybean. Coupling this research with an economic analysis of sequential preemergence and postemergence herbicide-based weed management systems, the projected trend is for more soil-applied herbicides to be used in conjunction with glyphosate in glyphosate-resistant crops. Results have been disseminated via Commodity Crops and Institute for Ag Professionals extension programming and incorporated into weed management recommendations published on the Applied Weed Science Research web site at http://appliedweeds.cfans.umn.edu/ PARTICIPANTS: F.R. Breitenbach (CPM Specialist Rochester, MN), L. M. Behnken (Regional Extension Educator Rochester, MN), J.K. Getting (Southwest Research and Outreach Center), T.R. Hoverstad and G.A. Johnson (Southern Research and Outreach Center), D.W. Miller and B.D. Kinkaid (Dept. of Agronomy and Plant Genetics). Opportunities for training and professional development provided by the project included participation in the Institute for Ag Professionals extension programming events held in January (Ag Professional Updates - 7 locations), July (Ag Professional Field School - one 2-day event with extensive hands-on training under field conditions) and the December (on 2-day Crop Pest Management Short Course). TARGET AUDIENCES: Crop consultants, seed and agrichemical dealers and other professionals who work with corn and soybean farmers were the target audience as they interact and are known at the local community level. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost-effective integrated weed management programs that will be implemented by producers. Implementation of integrated weed management programs will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from weed species shifts and the development of herbicide resistant weeds. Research results identified several weed species (Ambrosia trifida L., Ambrosia artemisifolia L. and Amaranthus rudis Sauer) that are present in some soybean and corn fields that are resistant to 4 to 8 times the label use rate of glyphosate in glyphosate-resistant crops and suggests the need for complimentary weed management tools to avoid significant changes in weed populations. Currently Minnesota has approximately 50% of the corn and <2% of the soybean acres treated with a preemergence, soil-residual herbicide. Due to the emergence of glyphosate resistance and the favorable economics and improvements in timeliness of glyphosate application when preemergence herbicides precede glyphosate application, look for an increase in the use of preemergence herbicides in Minnesota corn and soybean cropping systems.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. Results were published that assess the risk of weed escapes due to a weed species long- or late-emergence pattern in relation to the time of application of glyphosate in glyphosate-resistant soybean. In a concurrent study, common waterhemp (Amaranthus rudis Sauer) emergence patterns
were simulated by transplanting seedlings into corn and soybean at differing crop growth stages during two growing seasons. Results have been disseminated via Commodity Crops and Institute for Ag Professionals extension programming and incorporated into weed management recommendations published on the Applied Weed Science Research web site at http://appliedweeds.cfans.umn.edu/
PARTICIPANTS: Producers and ag professionals such as crop consultants and agronomists.
TARGET AUDIENCES: Producers and ag professionals such as crop consultants and agronomists.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost-effective integrated weed management programs that will be implemented by producers. Implementation of integrated weed management programs will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from weed species shifts and the development of herbicide resistant weeds. Research results identified several weed species (Chenopodium album L., Amaranthus spp. and Solanum ptychanthum Dunal) that could increase within the continued use of glyphosate in glyphosate-resistant crops and suggests the need for complimentary weed management tools to avoid significant changes in weed populations. Common waterhemp grown with corn was always shaded by the crop canopy but produced seed even when transplanted at the V10 corn growth stage. In soybean, weeds transplanted before the V4 growth stage
were taller than soybean and produced more seeds than when transplanted into corn up to the V4 growth stage. However, weeds transplanted after V5 into soybean produced no seed. Therefore, control of late-emerging common waterhemp may not be needed in soybean but may be justified in corn.
Publications
- Scursoni, J. A., F. Forcella, and J. L. Gunsolus. 2007. Weed escapes and delayed weed emergence in glyphosate-resistant soybean. Crop Protection 26: 212-218.
- Uscanga-Mortera, E., S. A. Clay, F. Forcella, and J. L. Gunsolus. 2007. Common waterhemp growth and fecundity as influenced by emergence date and competing crop. Agron. J. 99: 1265-1270.
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Progress 01/01/06 to 12/31/06
Outputs
The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. Results were published that assessed a range of different herbicide management practices, in two distinct cropping areas of Minnesota (Waseca and Lamberton), from an economic and agronomic risk management perspective. Economic analysis techniques of: mean-variance and stochastic
dominance were used. Results indicate that different herbicide management practices can result in different outcomes for the farmer, depending upon risk attitudes. To illustrate, under a given set of weed species, a risk-averse farmer would choose a lower-cost weed control program that involved just one trip through a field; however, this might not be the best option considering potential changes in weed emergence patterns, application timing concerns, and environmental limitations to field working days.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost-effective integrated weed management programs that will be implemented by producers. Implementation of integrated weed management programs will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from weed species shifts such as the development of herbicide resistant weeds.
Publications
- Hoverstad, T.R., Johnson, G.A., Gunsolus, J.L. and King, R.P. 2006. Evaluating the economic risk of herbicide-based weed management systems in corn and soybean using stochastic dominance testing. Weed Technol. 20:422-429.
- Scursoni, J., Forcella, F., Gunsolus, J., Owen, M., Oliver, R., Smeda, R. and Vidrine, R. 2006. Weed diversity and soybean yield with glyphosate management along a north-south transect in the United States. Weed Sci. 54:713-719.
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Progress 01/01/05 to 12/31/05
Outputs
The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. Results from a study evaluating the effect of time of day of application on the efficacy of two postemergence herbicides, glyphosate and glufosinate indicate that applications made during the period of 9 a.m. through 6 p.m. are more efficacious than applications in the evening
and early morning hours. The differences across time of application were large enough to warrant consideration of the practical importance of the time of application at which glyphosate and glufosinate are applied. Applicators should try to avoid early morning and evening hour applications of glyphosate and glufosinate, especially under cooler environments and on difficult-to-control or taller weed species.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost-effective integrated weed management programs that will be implemented by producers. Implementation of integrated weed management programs will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from weed species shifts such as the development of herbicide resistant weeds.
Publications
- Martinson, K. B., B. R. Durgan, J. L. Gunsolus, and R. B. Sothern. 2005. Time of day of application effect on glyphosate and glufosinate efficacy. Online. Crop Management doi:10.1094/CM-2005-0719-02-RS.
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Progress 01/01/04 to 12/31/04
Outputs
The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. To facilitate this process a team approach to developing a more effective means by which to communicate the need for the adoption of integrated weed management practices is in place. The goal of the team is to research the use of "knowledge networks" (a.k.a "learning groups").
The learning groups consist of small groups (10 to 15 people) of people from relevant sectors of the farming community (farmers, extension educators, crop consultants, input suppliers, and researchers) who meet on a regular basis to better understand a complex system such as integrated weed management. This approach is useful in helping people work through the complex farm-management issues that arise when you begin to implement integrated weed management practices. This project also continues to address integrated weed management from an economic risk management perspective. Herbicide evaluation protocols have been implemented that make it possible to evaluate the impact of environment and weed species on various chemical and mechanical weed management strategies.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost- effective integrated weed management programs that will be implemented by producers. Implementation of integrated weed management programs will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from weed species shifts such as the development of herbicide resistant weeds.
Publications
- Hoverstad, T. R., J. L. Gunsolus, G. A. Johnson and R. P. King. 2004. Risk-efficiency criteria for evaluating economics of herbicide-based weed management systems in corn. Weed Technol. 18:687-697.
- Jordan, N., H. Blissett, S. Simmons, R. Becker, J. Gunsolus and S. White. 2004. Learning groups for implementation of integrated weed management: principles and practical guidelines. Chapter 25 In Handbook of Sustainable Weed Management, Hawthorn Press.
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Progress 01/01/03 to 12/31/03
Outputs
The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. To facilitate this process a team approach to developing a more effective means by which to communicate the need for the adoption of integrated weed management practices is in place. The goal of the team is to research the use of knowledge networks (a.k.a. learning groups). The
learning groups consist of small groups (10 to 15 people) of people from relevant sectors of the farming community (farmers, extension educators, crop consultants, input suppliers, and researchers) who meet on a regular basis to better understand a complex system such as integrated weed management. This approach is useful in helping people work through the complex farm-management issues that arise when you begin to implement integrated weed management practices. This project also continues to address integrated weed management from an economic risk management perspective. Herbicide evaluation protocols have been implemented that make it possible to evaluate the impact of environment and weed species on various chemical and mechanical weed management strategies. I was invited to participate in a two-day Lime, Fertilizer, and Pesticide Conference at The Pennsylvania State University where I spoke to 200 people about Economic Risks of Weed Control Programs in Corn/Soybeans and Weed
Control Economics for Pennsylvania. I was also invited to the Fourth National Integrated Pest Management Symposium to present a paper on Connecting Growers & Consultants: Communicating Economic Risks and Value of IPM.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost-effective integrated weed management programs that will be implemented by producers. Implementation of integrated weed management programs will reduce their exposure to the short-term economic risks that result from poor timing of weed control practices and the longer-term risks that result from weed species shifts such as the development of herbicide resistant weeds.
Publications
- Sheaffer, C.C., Gunsolus, J.L., Jewett, J.G., and Lee, S.H. 2002. Annual Medicago as a smother crop in soybean. J. Agronomy & Crop Sci. 188:408-416.
- Jordan, N., Becker, R., Gunsolus, J., White, S., and Damme, S. 2003. Knowledge networks: an avenue to ecological management of invasive weeds. Weed Sci. 51:271-277.
- Miller, R.P., Martinson, K.B., Sothern, R.B., Durgan, B.R. and Gunsolus, J.L. 2003. Circadian response of annual weeds in a natural setting to high and low application rates of four herbicides with different modes of action. Chronobiology International 20(2):299-324.
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Progress 01/01/02 to 12/31/02
Outputs
The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. To facilitate this process a team approach to developing a more effective means by which to communicate the need for the adoption of integrated weed management practices is in place. The goal of the team is to research the use of "knowledge networks" (a.k.a. "learning groups").
The learning groups consist of small groups (10 to 15 people) from relevant sectors of the farming community (farmers, extension educators, crop consultants, input suppliers, and researchers) who meet on a regular basis to better understand a complex system such as integrated weed management. In the learning group everyone is a learner and everyone is a teacher. This approach is useful in helping people work through the complex farm-management issues that arise when you begin to implement integrated weed management practices. Ready-made solutions to production problems do not exist nor can each farmer implement identical solutions on their farm (i.e., there is no one correct answer or single source of authority). This project also continues to address integrated weed management from an economic risk management perspective. Herbicide evaluation protocols have been implemented that make it possible to evaluate the impact of environment and weed species on various chemical and mechanical
weed management strategies. A six-year database was a key resource for the completion of an M.S. thesis project focused on integrated weed management in corn and soybean cropping systems. Corn weed management systems that include a soil-applied herbicide followed by a postemergence herbicide reduced risk and was as economically profitable as the one-pass postemergence weed management option. In soybeans, however, the use of glyphosate as a two-pass total postemergence tactic was an economically stable weed management approach. Overuse of the glyphosate system may result, however, in shifting the weed spectrum to weeds that emerge later in the growing season and emphasizes the need for diversification of weed management tactics.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost- effective integrated weed management programs that will be implemented by producers.
Publications
- Jordan, N., J. Gunsolus, R. Becker, and S. White. 2002. Public scholarship-linking weed science with public work (Invited article). Weed Sci. 50: 547-554.
- Hoverstad, T. R. 2002. A risk management approach to herbicide evaluation. M. S. Thesis. (J.L. Gunsolus and G.A. Johnson (co-advisors).
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Progress 01/01/01 to 12/31/01
Outputs
The variability inherent in agriculture influences many crop production decisions, including weed management. Farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. This project continues to address integrated weed management from this risk management perspective. Herbicide evaluation protocols have been implemented that make it possible to evaluate the impact of environment and weed species on various chemical and mechanical weed
management strategies. A six-year data base is a key resource for an on-going M.S. thesis project focused on integrated weed management in corn and soybean cropping systems. Preliminary results indicate that corn weed management systems that include either a soil-applied herbicide followed by either a postemergence herbicide or mechanical weed control reduce risk and are as economically profitable as one-pass total postemergence weed management options. In soybeans, however, the use of glyphosate as a one-pass total postemergence or following a soil-applied herbicide has proven to be an economically stable weed management approach. Overuse of the glyphosate system may result, however, in shifting the weed spectrum to weeds that emerge later in the growing season. This will be a focal point of future research.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost-effective integrated weed management programs that will be implemented by producers.
Publications
- Martinson, K.B., Durgan, B.R., Gunsolus, J.L., Koukkari, W.L. and Southern, R.B. 2001. Circadian response of annual weeds to glyphosate and glufosinate. Chronobiology International. (Accepted 8/15/01).
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Progress 01/01/00 to 12/31/00
Outputs
This project has begun to address integrated weed management from a risk management perspective. The variability inherent in agriculture influences many crop production decisions, including weed management. A review of the literature found that farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. Six years ago, modifications to existing herbicide evaluation protocols were implemented that are making it possible to evaluate the impact of
environment and weed species on various chemical and mechanical weed management strategies. This data base is a key resource for an ongoing M.S. thesis project focused on integrated weed management in corn and soybean cropping systems. A two-year grant from the North Central Region IPM program focused on working with a group of soybean producers to develop a collaborative learning network in weed management is helping both the researcher and farmer to better link knowledge about weeds with the skills, equipment, and time resources necessary to develop diversified weed management systems. The farmers have responded to this program in a very positive way and the project is giving insight as to how to construct educational materials related to integrated weed management that will increase adoption of integrated weed management practices by farmers.
Impacts
Expected impacts of this research are to assist corn and soybean producers in developing cost- effective integrated weed management programs that will be implemented by producers.
Publications
- Reuss, S.A., Buhler, D.D. and Gunsolus, J.L. 2000. Effects of soil depth and aggregate size on weed seed distribution and viability in a silt loam soil. Applied Soil Ecology 483:1-9.
- Gunsolus, J.L., Hoverstad, T.R., Potter, B.D. and Johnson, G.A. 2000. Assessing integrated weed management in terms of risk management and biological time constraints. In Emerging Technologies for Integrated Pest Management: Concepts, Research, and Implementation. G.G. Kennedy and T.B. Sutton (eds.). APS Press, pp 373-383.
- Jordan, N.R., White, S.K., Gunsolus, J.L., Becker, R.L. and Damme, S.R. 2000. Learning groups developing collaborative learning methods for diversified, site-specific weed management: a case study from Minnesota, USA. In Cow Up a Tree: Knowing and Learning for Change in Agriculture, Case Studies from Industrialized Countries. M. Cerf, D. Gibbon, B. Hubert, R. Ison, J. Jiggins, M. Paine, J. Proost, N. Roling (eds.). Institut National de la Recherche Agronomique (INRA), Versailles, France.
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Progress 01/01/99 to 12/31/99
Outputs
This project has begun to address integrated weed management from a risk management perspective. The variability inherent in agriculture influences many crop production decisions, including weed management. A review of the literature found that farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints. I was asked to participate in an International Conference on "Emerging Technologies for Integrated Pest Management: Concepts, Research and
Implementation" held in Raleigh, NC in March of 1999. The title of my presentation was "Assessing Integrated Weed Management in Terms of Risk Management and Biological Time Constraints." The APS Press has agreed to publish the Proceedings of this International Conference by early 2000.
Impacts
Expected impacts of this research are to assist corn and soybean producers in making better weed management decisions regardless of the weed management tactics used.
Publications
- Gunsolus, J.L. and Buhler, D.D. 1999. A risk management perspective on integrated weed management. J. Crop Prod. 2:167-187.
- Stahl, L.A.B., Johnson, G.A., Wyse, D.L., Buhler, D.D. and Gunsolus, J.L. 1999. Effect of tillage on Setaria spp. emergence and growth and implications on timing of glyphosate applications. Weed Sci. 47:563-570.
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Progress 01/01/98 to 12/31/98
Outputs
This project has begun to address integrated weed management from a risk management perspective. The variability inherent in agriculture influences many crop production decisions, including weed management. A review of the literature found that farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints.
Impacts
(N/A)
Publications
- Gunsolus, J. L. and D. D. Buhler. 1999. A risk management perspective on integrated weed management. J. Crop Prod. 2:167-187.
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Progress 01/01/97 to 12/31/97
Outputs
This project has begun to address integrated weed management from a risk management perspective. The variability inherent in agriculture influences many crop production decisions, including weed management. A review of the literature found that farmers perceive variability, or risk, associated with integrated weed management in terms of yield, economic returns, and time and labor management. Biological time constraints such as periodicity of weed emergence, rate of crop and weed growth and development, and critical periods of weed control can influence the outcome and acceptance of integrated weed management systems. A key component to developing successful integrated weed management systems lies in the ability of the crop producer to align individual time and labor management issues with existing biological time constraints.
Impacts
(N/A)
Publications
- Oriade, C. A., R. P. King, F. Forcella, and J. L. Gunsolus. 1996. A bioeconomic analysis of site-specific management for weed control. Rev. of Ag. Economics 18:523 - 535.
- Gunsolus, J. L. and D. D. Buhler. 1997. A risk management perspective on integrated weed management. J. Crop Prod. 2: (Accepted for publication).
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Progress 01/01/96 to 12/30/96
Outputs
WEEDSIM, a bioeconomic decision aid for the management of annual weeds in corn and soybean, was field tested in Minnesota for three years in both crops. The model makes recommendations for soil-applied weed control tactics based on weed seed content in the soil and postemergence decisions based on weed seedling densities. Weed control, crop yield, herbicide load, and economic return with model-generated treatments were compared to standard herbicide and mechanical control systems. In most cases the model-generated treatments controlled weeds as well as the standard herbicide treatment. Crop yield reflected differences in weed control. In corn, herbicide use decreased by 27% with the seed bank model and 68% with the seedling model, relative to the standard herbicide treatment. In soybean, herbicide use decreased by 47% with the seed bank model and 93% with the seedling model, relative to the standard herbicide treatment. In corn, economic return to weed control was not
increased by using model-generated control recommendations. In soybean, economic return was increased 50% of the time using the model generated recommendations.
Impacts
(N/A)
Publications
- BUHLER, D.D., R.P. KING, S.W. SWINTON, J.L. GUNSOLUS, AND F. FORCELLA. 1996. Field evaluation of a bioeconomic model for weed management in corn (Zea mays). Weed Sci. 44:915-923.
- BUHLER, D.D., R.P. KING, S.W. SWINTON, J.L. GUNSOLUS, AND F. FORCELLA. 1997. Field evaluation of a bioeconomic model for weed management in soybean (Glycine max). Weed Sci. (In Press).
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Progress 01/01/95 to 12/30/95
Outputs
WEEDSIM, a bioeconomic decision aid for the management of annual weeds in corn and soybean, was field tested for four years in Minnesota. WEEDSIM has been validated for a limited number of important and prevalent annual weed species including; common lambsquarters (Chenopodium album), green and yellow foxtail (Setaria viridis and lutescens, respectively), redroot pigweed (Amaranthus retroflexus), wild mustard (Brassica kaber), and Pennsylvania smartweed (Polgonum pensylvanicum). After four years of applying WEEDSIM recommendations to the same plots, there were no increases in annual weeds densities or decreases in weed control or crop yields as compared to a herbicide treatment that is standard for the cropping region. Frequently, WEEDSIM recommendations resulted in a reduction in herbicide inputs and costs as compared to the standard treatment. A variant of WEEDSIM was developed to study the potential economic and environmental benefits of site-specific management
(SSM). Findings show that patchiness in weed distributions plays a key role in the usefulness of SSM as a weed control tool and its impact on profit is modest. Only when weed populations were extremely patchy and of high density did the SSM strategy prove to be more profitable than a single appliction to an entire field.
Impacts
(N/A)
Publications
- BUHLER, D.D. AND J.L. GUNSOLUS. 1995. Effect of date of preplant tillage and planting on weed populations and mechanical weed control in soybean (Glycine max). Weed Sci. (in-press).
- FORCELLA, F., R.P. KING, S.M. SWINTON, D.D. BUHLER, AND J.L. GUNSOLUS. 1995. Multi-year validation of a decision aid for integrated weed management in row crops. Weed Sci. (in-press).
- ORIADE, C.A. 1995. A bioeconomic analysis of site-specific management and delayed planting strategies for weed control. Ph.D. Thesis, Graduate School, Univ. of Minn.
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Progress 01/01/94 to 12/30/94
Outputs
Field research conducted over several growing seasons to study weed/crop interactions has resulted in improved understanding of the demographic processes regulating the population dynamics of velvetleaf (Abutilon theophrasti) in soybean (Glycine max) as part of a corn (zea mays) - soybean rotation. Over the growing seasons of 1992 and 1993, a consistent 6.8% of the total velvetleaf seedbank emerged each year, however, cumulative velvetleaf seedling emergence was delayed in 1993 compared to 1992. The probability of velvetleaf seedlings surviving each year varied significantly across time of emergence and less than 21% of all velvetleaf seedlings survived each year in mixture with soybean, due in part to Verticillium spp. wilt infection. Velevetleaf survival and seed production were significantly reduced in mixture with the crop in both years. A simulation model was developed to predict the population dynamics and economics of velvetleaf in a corn-soybean rotation and to
assess the impact of an infection by a Verticillium spp of wilt on velvetleaf. Model predictions estimate that infected velvetleaf populations would have a seedbank density of approximately 80 seeds per square meter, uninfected populations would oscillate between 400 and 4000 seeds per square meter. Velvetleaf populations that were infected 8 out of 20 years increased annualized economic returns by 8% and the number of years that control was necessary was reduced by 13%, as compared to an uninfected population.
Impacts
(N/A)
Publications
- BUHLER, D.D., D.E. STOLTENBERG, R.L. BECKER, AND J.L. GUNSOLUS. 1994. Perennial weed populations after 14 years of variable tillage and cropping practices. Weed Sci. 42:205-209.
- LINDQUIST, J.L., B.D. MAXWELL, D.D. BUHLER, AND J.L. GUNSOLUS. 1994. Velvetleaf (Abutilon theophrasti) recruitment, survival, seed production, and interference in soybean (Glycine max). Weed Sci. (in-press).
- LINDQUIST, J.L., B.D. MAXWELL, D.D. BUHLER, AND J.L. GUNSOLUS. 1994. Modeling the population dynamics and economics of velvetleaf (Abutilon theophrasti) in a corn (Zea mays) - soybean (Glycine max) rotation. Weed Sci. (in-press).
- SWINTON, S.M., D.D. BUHLER, F. FORCELLA, J.L. GUNSOLUS, AND R.P. KING. 1994. Estimation of crop yield loss due to interference by multiple weed species. Weed Science 42:103-109.
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Progress 01/01/93 to 12/30/93
Outputs
Research in soybean on the integration of mechanical weed control with reduced postemergence herbicide inputs was completed and published in Weed Science. The research evaluated the effectiveness of reduced rates of bentazon broadcast- or band-applied over the crop row in combination with interrow cultivation for common cocklebur control in soybean. When environmental conditions were favorable, a majority of the common cocklebur emerged prior to bentazon application. As A result, bentazon at 0.6 kg ai/ha applied in a 38-cm-wide band over the soybean row followed by two cultivations controlled almost 90% of the common cocklebur. This is a 88 % reduction in bentazon use. However, when precipitation was below normal prior to bentazon application and a high proportion of the common cocklebur emerged after the initial bentazon was applied, sequential bentazon treatments controlled more common cocklebur and resulted in greater soybean yields than combinations of bentazon
plus cultivation. Therefore, greater management effort will be required if producers attempt to utilize reduced bentazon rates plus cultivation versus standard bentazon rates. Research is also continuing to evaluate a corn and soybean bioeconomic weed management model in order to lower herbicide inputs without sacrificing weed control, yield, and net return.
Impacts
(N/A)
Publications
- BUHLER, D.D., GUNSOLUS, J.L. and RALSTON, D.F. 1993. Common cocklebur (Xanthium strumarium) control in soybean (Glycine max) with reduced bentazon rates and cultivation. Weed Sci. 41:447-453.
- BUHLER, D.D., KING, R.P., GUNSOLUS, J.L., SWINTON, S.W. and FORCELLA, F. 1993. Field evaluation of a bioeconomic weed management model for corn. Proc. North Centr. Weed Sci. Soc. 47:135.
- FORCELLA, F., BUHLER, D.D., SWINTON, S.M., KING, R.P., GUNSOLUS, J.L. and MAXWELL, B.D. 1993. Field evaluation of a bioeconomic weed management model for the Corn Belt, U.S.A. 8th EWRS Symposium: Quantitative approaches on weed and herb.
- FORCELLA, F., KING, R., WILES, L., BUHLER, D., SWINTON, S., GUNSOLUS, J. and MAXWELL, B. 1993. Bioeconomic weed management models. Hort Sci. 28:152.
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Progress 01/01/92 to 12/30/92
Outputs
Research with soybean on the integration of mechanical weed control with reducedsoil-applied herbicide inputs was completed and published in the Agronomy Journal. The research evaluated the effectiveness of reduced rates of broadcast-or band-applied alachlor plus metribuzin and rotary hoeing, each in combination with between-row cultivation over two cropping seasons. Results differed between the two years. In 1989, under low weed densities, several mechanical weed control systems resulted in soybean yields similar to the weed-free control. In 1990, under greater weed densities, mechanical weed control systems resulted in reduced soybean yields compared to weed control systems that included herbicides. Based on the results of this research, switching from chemical-intensive systems to mechanical weed management systems under high weed pressure is not advisable. Under high weed pressure, reduced rates of herbicide broadcast or banded over the row, in combination with
cultivation, provided excellent weed control. Research is continuing on determining the efficacy of several new postemergent corn and soybean herbicides on wild proso millet and woolly cupgrass. Research results indicate that two newly introduced herbicides: nicosulfuron in corn, and clethodim in soybeans, are highly effective in controlling these weed species. However, sole reliance on these herbicides would be impractical due to the extended germination period of these weeds.
Impacts
(N/A)
Publications
- BUHLER, D.D., GUNSOLUS, J.L. and RALSTON, D.F. 1992. Integrated weed management techniques to reduce herbicide inputs in soybean. Agron. J. 84:973-978.
- LUESCHEN, W.E., HOVERSTAD, T.R. and GUNSOLUS, J.L. 1992. Wild-proso millet control in corn. North Centr. Res. Report. 49:122-123.
- LUESCHEN, W.E., HOVERSTAD, T.R. and GUNSOLUS, J.L. 1992. Woolly cupgrass control in corn. North Centr. Res. Report. 49:196-197.
- LUESCHEN, W.E., HOVERSTAD, T.R. and GUNSOLUS, J.L. 1992. Woolly cupgrass and volunteer corn control in soybean. North Centr. Res. Report. 49:258-259.
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Progress 01/01/91 to 12/30/91
Outputs
A review of the literature on mechanical and cultural weed control in corn and soybeans was conducted and published in the American Journal of Alternative Agriculture. Current research emphasis is on integrating mechanical weed control into chemically intensive corn and soybean weed management programs. The influence of reduced postemergence corn and soybean herbicide rates on weed control and economic returns is currently under investigation. There is one graduate student assigned to the soybean project. Results indicate that the following herbicides: bentazon, acifluorfen, and sethoxydim can be used at one-half of label use rates and consistently control weeds if the following procedures are followed: 1. Early application, 14 to 21 days after soybean planting. 2. Application to weeds approximately 5 cm tall, or less. 3. Fields must be cultivated 1 to 2 weeks after herbicide application to control late weed flushes. Two new postemergence corn herbicides
(nicosulfuron and primisulfuron) and two new soybean herbicides (imazethapyr and thifensulfuron) have recently been registered. Research investigating the influence of application time and herbicide rate on the efficacy of these four herbicides on 13 weed species was conducted. Results were species specific. Recently registered imidazolinone (imazethapyr) and sulfonylurea (thifensulfuron and chlorimuron) herbicides have occasionally caused injury to soybeans in Minnesota.
Impacts
(N/A)
Publications
- GUNSOLUS, J.L. 1990. Mechanical and cultural weed control in corn and soybeans. Am. J. Alt. Ag. 5:114-119.
- LUESCHEN, W.E., GUNSOLUS, J.L. and HOVERSTAD, T.R. 1991. Effects of rotary hoe and reduced herbicide rates on weed control in soybean. North Centr. Res. Report. 48:262-263.
- BUHLER, D.D., GUNSOLUS, J.L. and RALSTON, D.F. 1991. Influence of application time on weed control with reduced rates of primisulfuron and nicosulfuron in a weed nursery. North Centr. Res. Report. 48:155-156.
- BUHLER, D.D., GUNSOLUS, J.L. and RALSTON, D.F. 1991. Influence of application time on weed control with reduced rates of imazethapyr and thifensulfuron in a weed nursery. North Centr. Res. Report. 48:264-265.
- GUNSOLUS, J.L., LUESCHEN, W.E., SCHMITT, R.M. and RATHMANN, D. P. 1991. Effects of planting date, application timing, and additives on soybean tolerance to postemergence applications of imidazolinone and sulfonylurea herbicides at Wasec.
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Progress 01/01/90 to 12/30/90
Outputs
Research on the effectiveness of mechanical weed control practices in corn and soybeans is currently under investigation. A review of the literature on mechanical and cultural weed control in corn and soybeans was conducted and has been accepted for publication in the American Journal of Alternative Agriculture. The research data base that is currently being developed will be used to assess the economic and time management constraints of mechanical weed control. The influence of reduced postemergence soybean herbicide rates on weed control and economic returns is currently under investigation. There is one graduate student assigned to the project. Results indicate that the following herbicides: bentazon, acifluorfen, and sethoxydim can be used at one-half of label use rates and consistently control weeds if the following procedures are followed: 1. Early application, 14 to 21 days after soybean planting. 2. Application to weeds approximately 5 cm tall, or less. 3.
Fields must be cultivated 1 to 2 weeks after herbicide application to control late weed flushes. Two new herbicides (nicosulfuron and primisulfuron) have been registered for use for postemergence grass control in corn. Unfortunately, certain organophosphate insecticides used for corn rootworm control can predispose the corn plants to significant crop injury potential if nicosulfuron or primisulfuron are applied.
Impacts
(N/A)
Publications
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