Source: NORTH CAROLINA STATE UNIV submitted to NRP
WEED MANAGEMENT TECHNIQUES FOR FRUITS AND VEGETABLES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0196290
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2009
Project End Date
Sep 30, 2014
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695
Performing Department
Horticultural Science
Non Technical Summary
Growers are viewing vegetables and fruits as crops that have potential to increase their farm income. However they face intensively managed crops lacking effective herbicides with only a few herbicides being developed. Ineffective weed management programs results in an average of 20 to 25% loss in production and revenues annually. Estimates of 60 to 70% of the NC sweetpotato acreage experiences up to 30% yield and quality reduction from primarily Palmer amaranth. In addition, several herbicide resistant weed species have been identified in NC and are increasing exponentially in vegetables and fruits. In addition to reducing yield and quality weeds also interfere with harvest. This interference is exacerbated in many crops in NC because they are hand harvested and harvesters are paid based on quantity of produce harvested (ie buckets of no. 1 sweetpotato roots picked up and poured into bins). Weeds can also cause an increase in other pests (diseases, insects, animal) and can contaminate (ie nutsedge penetrating potato tubers or cantaloupe fruit; cocklebur fruit in green crops). In grown vegetable and fruit crops, the high cost of labor and mechanical cultivation for weed control necessitate the use of herbicides. The lack of EPA-registered herbicides for these crops has always been anobstacle to attaining optimum production of vegetables and fruits. Herbicide development in vegetable and fruit crops is now almost totally through the IR-4 program because these crops are grown on few acres compared to agronomic crops. Fear of damage claims to high value vegetable and fruit crops, low relative acreage of these crops, and the high cost of development discourage manufacturers from developing new herbicide registrations for these crops. As a result, much of the work must be conducted by the state agricultural research services (SARS) cooperation with IR-4 and industry. The impending loss of methyl bromide will also greatly reduce growers ability to control troublesome weeds in certain vegetable and fruit crops until alternative strategies are developed. Growers of these crops have long depended on methyl bromide for controlling most pests including weeds. With respect to weeds, the void from loss of methyl bromide brings will need to filled for the most part with herbicide systems. Growers of vegetable and fruit crops have large investments (production costs,etc.) in their crops. Growers have to develop a weed management program for each field they farm, specific to the weed problem and crop. They sometimes struggle with many decisions involved in developing and implementing a weed management program. Specifically, decision-making involves methods of weed control and timing of various methods of weed control (herbicide, cultivation, hand removal, etc), herbicide application (ie directed vs. broadcast). This research project will involve field and greenhouse research in vegetables and fruits that will address the problems related to weeds threatening these crops. The resulting impact of this research will be more efficient production systems, reduction of impact of weeds on quality and yield, and more abundant supply of these food crop products.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2131450114050%
2131460114015%
2131461114015%
2131110114010%
2131114114010%
Knowledge Area
213 - Weeds Affecting Plants;

Subject Of Investigation
1114 - Peach; 1110 - Apple; 1450 - Sweet potato; 1460 - Tomato; 1461 - Peppers;

Field Of Science
1140 - Weed science;
Goals / Objectives
The overall objective is to conduct research to support development of weed management programs/strategies for vegetables and fruits. The following specific objectives will accomplish this overall objective. Weed biology: a)Determine the critical weed-free period of specific weeds in certain vegetable crops and fruits. Weed management: a)Determine tolerance of crop cultivars to currently registered and non-registered herbicides and to develop methods for improving tolerance. b)Evaluate chemical and non-chemical methods for efficacy and safety in fruits and vegetable crops. This objective includes methyl bromide replacements, and IR-4 trials. From this research, efficacy of chemical and non-chemical methods will be determined. Efficacy and weed biology data will be used in the future to develop computer aided program to assist growers in developing an effective weed management program. c)Modify current weed management systems--including developing weed management strategies for conventional crops and developing weed management strategies for crops grown in minimum tilled crops. d)Develop systems that focus on control of specific problem weeds (ie resistant weeds, perennial weeds such as nutsedge, etc). e)I will continue to serve as director of the regional IR-4 research center at North Carolina State University.
Project Methods
Objective 1. The critical weed-free period for three of North Carolina's major vegetable crops (pepper, grafted tomato, sweetpotato) will be determined using a conventional additive technique involving removal and plant back of weeds (Oliver 1988). The weeds included in these studies will be the most common and/or troublesome weeds as determined by surveying (mail-in, telephone, etc) North Carolina producers. In the removal studies, weeds that emerge with the crop will be removed (chemically or by hand) at various times after emergence or transplanting, and then plots maintained weed-free for the rest of the season. In the plant back studies, weeds are allowed to emerge or are seeded at various times after emergence or transplanting. The experimental design will either be a randomized complete block or factorial on a randomized complete block. Treatments will be replicated 4 to 6 times. Data will include quality, yield, biomass and others and will be analyzed by regression. The environmental factors such as light, soil moisture and nutrients will be measured by scientific instrumentation. Objective 2a. Cultivar/herbicide interaction studies will be conducted to determine tolerance of vegetable and fruit crops to herbicides. Methods for increasing tolerance to be evaluated may include post-directed application, drip application and other methods and materials (herbicides, mulches, etc.). Herbicides or potential herbicides will be sprayed at one-half, one and two times the normal use or labeled rate. Experimental design will be a randomized complete block or a split plot. Treatments will be replicated 4 times. In cases where crop tolerance needs to be increased, experiments will be conducted to improve tolerance. Objective 2b. Field experiments will be conducted in various vegetable and fruit crops to determine the efficacy and crop safety of potential herbicides. These experiments will be used to develop successful management programs for the most troublesome weeds included herbicide resistant weeds in vegetable and fruit crops. The studies will be conducted on research stations and on-farm. Plot size will range from 80 to 300 square feet depending on the nature of the study. Treatments will be randomized three to four times in either a randomized complete block or a split plot design. Herbicide treatments will be applied with a CO2 backpack sprayer and where soil incorporation is needed a tractor-mounted tiller will be used. Crop response (height, injury, stand etc.), weed control and yield (quantity and quality) will be recorded.

Progress 10/01/09 to 09/30/14

Outputs
Target Audience:The target audience for this project includes growers and personnel working in vegetable and small fruit production. The target audience also includes personnel working in the agricultural chemical supply industry. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project has allowed for opportunites to train graduate students and Extension agents, and to provide information on optimum weed-free strip width to blackberry growers. How have the results been disseminated to communities of interest?The results have been disseminated to the growers, Extension agents and specialists, and agricultural chemical suppliers through field days, publications and Research and Extension meetings with growers. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Sweetpotato growers expressed interest in being able to apply a herbicide POST-directed just prior to layby to control late emerging weeds. Thus, studies were completed on Covington sweetpotato tolerance to flumioxazin herbicide POST-directed. In addition studies were conducted to determine the optimum weed-free strip width on blackberry growth, yield and fruit quality.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Meyers, S.L., K.M. Jennings, D.W. Monks and W.E. Mitchem. 2014. Effect of weed-free strip width on Navaho blackberry growth, yield and fruit quality. Weed Technol. 28(2):426-431. Meyers, S.L., K.M. Jennings, and D.W. Monks. 2014. Covington sweetpotato tolerance to flumioxazin applied POST-directed. Weed Technol. 28(1).


Progress 10/01/12 to 09/30/13

Outputs
Target Audience:Field days and grower meetings were participated in to transfer technology to growers for adoption on their farms. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This work has been presented to growers and those personnel working in small fruit crops, sweetpotato and tomato at field days, and various meetings across North Carolina. In addition, this information is published in technical publications for use and adoption by growers and technical advisors working in these crops. How have the results been disseminated to communities of interest?The results of these studies have been disseminated through publications, field days, and Research and Extension meetings. What do you plan to do during the next reporting period to accomplish the goals?The plan is to report on weed control research in blackberry.

Impacts
What was accomplished under these goals? Programs for controlling weeds in small fruit crops and sweetpotato were developed through Research and Extension programs. The control programs in sweetpotato were focused on the weed Palmer amaranth. Herbicide programs for blueberry were focused onthe Carolina redroot. The critical period of contorl forPalmer amaranth in fresh market tomato was determined through research studies.

Publications

  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Pekarek, R.A., D.W. Monks, K.M. Jennings, and G.D. Hoyt. 2013. Bell Pepper (Capsicum annuum) tolerance to imazosulfuron and thifensulfuron-methyl. Weed Technol. 27:741-746. Meyers, S.L., K.M. Jennings, D.W. Monks, D.L. Jordan, and J.R. Ballington. 2013. Effects of PRE and POST herbicides on Carolina redroot (Lachnanthes caroliniana) growth. Weed Technol. 27:747-751. Meyers, S.L., K.M. Jennings, D.W. Monks, D.K. Miller, and M.W. Shankle. 2013. Rate and application timing effects on tolerance of Covington sweetpotato to S-metolachlor. Weed Technol. 27:729-734. Meyers, S.L., K.M. Jennings, D.W. Monks, J.R. Ballington, and D.L. Jordan. 2013. POST control of Carolina redroot (Lachnanthes caroliniana). Weed Technol. 27:534-537. Meyers, S.L., K.M. Jennings, and D.W. Monks. 2013. Herbicide-based weed management programs for Palmer amaranth (Amaranthus palmeri) in sweetpotato. Weed Technol. 27:331-340. Dittmar, P.J., D.W. Monks, K.M. Jennings, and J.R. Schultheis. 2013. Effects of halosulfuron POST on sweetpotato yield and storage root quality. Weed Technol. 27:113-116. Garvey, P.V., S.L. Meyers, D.W. Monks and H.D. Coble. 2013. Influence of Palmer amaranth on the critical period for weed control in plasticulture-grown tomato. Weed Technol. 27:165-170.


Progress 10/01/11 to 09/30/12

Outputs
Target Audience:The target audiences for thisproject werefarmers (both large and small operations) with most beingfamily farming operations with diverse operations. North Carolina is the third most diverse state in the U.S. based on the diversity of crops grown below on California and Florida.The efforts were focused on developing a research based solution and then transfering the technology developed to farmers through our Cooperative Extension program. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The eight graduate students working in this project were trained in applied weed science, project management, strategic planning of how to develop a strategy for addressing issues by growers through research and Extension. How have the results been disseminated to communities of interest?The results of this research have been disseminated through publishing this information through grower related meetings and field days, weed science related professional meetings, publication in professional journals, county Extension staff/faculty and direct communication to farmers. 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 results from this research benefits growers directly by being provided to growers, and extension and industry personnel working with growers. This research has been used to develop new herbicide registrations, new recommendations in chemical and non chemical weed control, and to assist growers with making decisions regarding weed management. For example, over 90% of the current weed management programs used by growers in sweetpotatoes were developed by collaborations of this program with those faculty listed as collaborators in this project.

Publications

  • Type: Journal Articles Status: Published Year Published: 2012 Citation: Pekarek, R.A., D.W. Monks, K.M. Jennings, and G.D. Hoyt. 2013. Bell Pepper (Capsicum annuum) tolerance to imazosulfuron and thifensulfuron-methyl. Weed Technol. 27:741-746. Meyers, S.L., K.M. Jennings, D.W. Monks, D.L. Jordan, and J.R. Ballington. 2013. Effects of PRE and POST herbicides on Carolina redroot (Lachnanthes caroliniana) growth. Weed Technol. 27:747-751. Meyers, S.L., K.M. Jennings, D.W. Monks, D.K. Miller, and M.W. Shankle. 2013. Rate and application timing effects on tolerance of Covington sweetpotato to S-metolachlor. Weed Technol. 27:729-734. Meyers, S.L., K.M. Jennings, D.W. Monks, J.R. Ballington, and D.L. Jordan. 2013. POST control of Carolina redroot (Lachnanthes caroliniana). Weed Technol. 27:534-537. Meyers, S.L., K.M. Jennings, and D.W. Monks. 2013. Herbicide-based weed management programs for Palmer amaranth (Amaranthus palmeri) in sweetpotato. Weed Technol. 27:331-340. Dittmar, P.J., D.W. Monks, K.M. Jennings, and J.R. Schultheis. 2013. Effects of halosulfuron POST on sweetpotato yield and storage root quality. Weed Technol. 27:113-116. Garvey, P.V., S.L. Meyers, D.W. Monks and H.D. Coble. 2013. Influence of Palmer amaranth on the critical period for weed control in plasticulture-grown tomato. Weed Technol. 27:165-170. Meyers, S.L., K.M. Jennings, W.E. Mitchem, and D.W. Monks. 2013. Effect of weed-free strip width on newly established Navaho blackberry growth, yield, and fruit quality. (accepted 11/13). Meyers, S.L., K.M. Jennings, and D.W. Monks. Covington sweetpotato tolerance to flumioxazin applied POST-directed. (accepted 8/13).


Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: Studies were conducted to determine vegetable and fruit crop tolerance to herbicides, the response of weeds to herbicides, and the relationship of weeds with crops (vegetable/fruits). Results from these trials are being used to develop weed management programs (models, control programs) for growers. This information directly supported growers by being presented at the National Sweetpotato Collaborators, Weed Science Society of America, IR-4 Food Use Workshop, Southeastern Vegetable and Fruit Exp, NC Tomato and Vegetable Winter meeting, NC Tomato and Vegetable Field Day, NC Winter Sweetpotato Research Grower meeting. Graduate students were trained in weed management, weed/crop relationships, vegetable/fruit weed management, weed identification and herbicide efficacy. Four graduate students began their program for degrees in applied Weed Science. PARTICIPANTS: David W. Monks is the principal investigator for this project. He is responsible for developing the objectives and the protocol for each study as well as providing input on initiating and conduct of the studies. Katie Jennings is a collaborator with this project. Partnership organizations include the NC SweetPotato Commission, NC Tomato Growers Association, NC Vegetable Growers Association, NC Blueberry Council, and NC Commercial Blackberry and Raspberry Growers Association. Other collaborators include faculty from University of Florida, Louisiana State University, Mississippi State University, Auburn University, University of California-Davis, Rutgers Univeristy (IR-4) and University of Arkansas. Graduate students include Stephen Myers, Sushila Chaudhari, Brandon Smith, Lauren Coleman, and Daniel Dayton. Also, faculty at NC State University that are collaborators include faculty in the Department of Entomology, Department of Crop Science, Department of Horticultural Science, Department of Plant Pathology,and Department of Soil Science. Industry collaborations include Gowan, Bayer, BASF, and Valent. TARGET AUDIENCES: Target audiences that receive this information include growers, extension agents, extension and research faculty, graduate students, and others technical representatives from industry and others across NC and the U.S. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The results from this research benefits growers directly by being provided to growers, and extension and industry personnel working with growers. This research has been used to develop new registrations, new recommendations, assist growers with making decisions regarding weed management. For example, over 80% of the current weed management programs used by growers in sweetpotatoes were developed by this program.

Publications

  • Dittmar, P.J., D.W. Monks, and K.M. Jennings. 2011. Effect of drip applied herbicides on plasticulture tomato and yellow nutsedge. Proc. South. Weed Sci. Soc. 64:49.
  • Meyers, S.L., K.M. Jennings, D.W. Monks, and W.E. Mitchem. 2011. Weed management in blackberry (Rubus spp.) production. Proc. South. Weed Sci. Soc. 64:314.
  • Jennings, K.M. and D.W. Monks. 2011. Herbicide Carryover. Proc. South. Vegetable and Fruit Expo. Myrtle Beach, SC.
  • Meyers, S.L., K.M. Jennings, and D.W. Monks. 2011. Palmer amaranth, a weed nemesis what will control it Proc. South. Vegetable and Fruit Expo, Myrtle Beach, SC.
  • Monks, D.W. and K.M. Jennings. 2011. Control of troublesome weeds in cucumber, carryover considerations and update on Palmer amaranth resistance. Proc. South. Vegetable and Fruit Expo, Myrtle Beach, SC.
  • Jennings, K.M., D.W. Monks, and W.E. Mitchem. 2011. Chemical control for vegetable crops. in NC Agricultural Chemicals Manual. pp 310-333.
  • Jennings, K.M., D.W. Monks, and W.E. Mitchem. 2011. Chemical control for small fruit crops. in NC Agricultural Chemicals Manual. pp 281-285.
  • Jennings, K.M., D.W. Monks, W.E. Mitchem, R.B. Batts, A.W. MacRae, and A.S. Culpepper. 2011. Chemical control for vegetable crops. in SE Vegetable Crop Handbook. pp 239-269.
  • Brannen, P., W. Cline, F. Hale, D. Horton, M. Czarnata, K. Jennings, W. Mitchem, D. Monks, D. Lockwood, G. Krewer, B. Bellinger, P. Guillebeau, and P. Smith. 2011. South. Regional Blueberry Integrated Management Guide.
  • Monks, D.W., M.W. Shankle, and K.M. Jennings. 2011. Herbicide injury. C.A. Clark, T.P. Smith, D.M. Ferrin, and G.J. Holmes (eds.), Compendium of Sweet Potato Dieseases. 2nd Edition. APS Press, St. Paul, MN, USA. (in press)


Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: Field days and meetings where information generated by studies in this project was presented to growers, extension specialists, researchers and extension agents included the NC Sweetpotato Field Day, NC Sweetpotato Commission Annual Meeting, NC Sweetpotato Collaborators, NC Vegetable and Tomato Field Day, and Southeastern Extension Vegetable Workers meeting. The audience for these activities comprised many of citizens of local communities and the audiences further disseminated the information presented at field days and meetings to other people interested in using this technology. PARTICIPANTS: The NC Tomato Growers Association, NC Sweetpotato Commission, NC Department of Agriculture and Consumer Services, and the NC Vegetable Growers Association all supported/collaborated on these projects. Graduate students were trained on applied research and extension programs in these crops. Technology from these studies was transferred through field days and meetings to growers, workers and industry representatives. TARGET AUDIENCES: Our target audiences are the citizens of North Carolina, primarily growers and people supporting the vegetable industries. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The outcome/impact of this research is development and adoption by growers of more effective programs for managing weeds especially in tomatoes, peppers and sweetpotatoes. The cost of labor to remove weeds in these crops is reduced based on the weed management programs developed from this research. At least $200 to $300 per acre is currently being saved through the use of these programs in these crops and through the reduction of labor for weed removal.

Publications

  • Pekarek, R., Monks, D.W., Garvey, P.V., Jennings, K.M., and MacRae, A.W. 2010. Effect of sulfentrazone herbicide on vegetable follow-crops. Weed Technol. 24:20-24.
  • Dittmar, P.J., Jennings, K.M., and Monks, D.W. 2010. Response of watermelon to rate and timing of imazosulfuron. Weed Technol. 24:127-129.
  • Dittmar, P.J., Monks, D.W., and Schultheis, J.R. 2010. Utilization of commercially available pollenizers for optimizing triploid watermelon production. HortScience 45(4):541-545
  • Meyers, S.L., Jennings, K.M., Schultheis, J.R., and Monks, D.W. 2010. Interference of Palmer amaranth (Amaranthus palmeri) in sweetpotato. Weed Sci. 58:199-203.
  • Meyers, S.L., Jennings, K.M., Schultheis, J.R., and Monks, D.W. 2010. Evaluation of flumioxazin and S-metolachlor rate and timing for Palmer Amaranth (Amaranthus palmeri) control in sweetpotato. 24:495-503.


Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Field studies were conducted in lettuce, pepper, tomato, peach, blueberry and sweetpotato to determine the best programs for controlling weeds. Vegetable research was primarily related to crop tolerance to herbicides and management of Palmer amaranth. Studies relating to weed management in fruit were related primarily to ground cover management in which various herbicides strips in the peach row were evaluated to determine the best method for producing peach quality and yield. Field days and grower meetings associated with sweetpotato, tomato and pepper studies were held in NC with many key growers and scientists from many states attending. In addition, much of the sweetpotato acreage in NC was represented by growers attending the field day. Four MS or Phd graduate students completed their degrees and graduated. Presentations were given at several scientific professional society meetings in which industry personnel, and university public outreach and research faculty attended. Dissemination of information from these studies is being done through the transfer of technology passed directly to growers, university extension faculty including agents, and industry personnel at field days and meetings using presentations and visual observation of studies in progress. PARTICIPANTS: Ryan Pekarek, graduate student, NC State Univ., Box 7609, Raleigh NC Peter Dittmar, graduate student, NC State Univ., Box 7609, Raleigh NC Juliana Buckelew, graduate student, NC State Univ., Box 7609, Raleigh NC Katie Jennings, res. assistant prof., NC State Univ., Box 7609, Raleigh NC Sue Langdon, Exec. Dir., NCSweetPotato Comm., 700 E. Parrish Dr., Benson NC Jonathan Schultheis, Prof., NC State Univ., Box 7609, Raleigh NC Wayne Mitchem, Ext. Assoc., NC State Univ., Box 7609, Raleigh NC TARGET AUDIENCES: The target audiences for this project are growers, university research and extension faculty including extension agents, industry representatives associated with crops, and graduate students. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The primary outcome or impact from this research is the development of weed management programs that are adopted by vegetable or fruit growers that will best manage weeds on their farms and increase farm income or quality of life. Programs involving several herbicides, not previously used in the respective crop but found crop safe and providing excellent postemergence weed control in our studies, have been identified for pepper, a crop which has few tools for weed control. Request for development and subsequent registration of the herbicide for pepper has been submitted to the National IR-4 program, and development toward registration is underway. Findings observed in the sweetpotato studies have determined that Palmer amaranth can cause severe reduction in yield and quality of storage roots even at low populations. Growers have made this observation and seen programs controlling this weed at the field days and outreach meetings, and they have adopted these management tools on their farms. Impact of wide spread grower adoption of optimum herbicide strip width in peach is anticipated, and is likely to occur in the near future as this technology is transferred through previous mentioned methods.

Publications

  • Norsworthy, J.K., Oliveira, M.J., Jha, P., Malik, M., Buckelew, J.K., Jennings, K.M., and Monks, D.W. 2008. Palmer amaranth and large crabgrass growth with plasticulture-grown pepper. Weed Tech. 22(2):296-302.
  • Dittmar, P.J., Monks, D.W., Schultheis, J.R., and Jennings, K.M. 2008. Effects of Postemergence and Postemergence-Directed Halosulfuron on Triploid Watermelon (Citrullus lanatus). Weed Tech 22(3):467-471.
  • Harrelson, E.R., Hoyt, G.D., Havlin, J.L., and Monks, D.W. 2008. Effect of planting date and nitrogen fertilization rates on no-till pumpkins. HortScience 43(3):1-5.
  • Sydorovych, O., Safley, C.D., Welker, R.M., Ferguson, L.M., Monks, D.W., Jennings, K.M., Driver, J., and Louws, F.J. 2008. Economic Evaluation of Methyl Bromide Alternatives for the Production of Tomatoes in North Carolina. HortTechnology 18:705-713.


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: Studies were conductd in blueberry, lettuce, sweetpotato, pepper, peaches and tomato to determine effective weed management programs for these crops. Studies were conducted at various research stations and some grower locations across North Carolina. Field days to disseminate information including weed management information to growers were held for blueberries, lettuce, sweetpotato, pepper and tomato. Meetings that included dissemination of production and pest management information along with weed management information were also held for each of these crops. PARTICIPANTS: Individuals involved in the research reported were faculty who actively participated in planning the research, and assisted with conducting and analyzing the data. Six graduate students were involved in the studies and were not only trained in research techniques but they also actively participated in the research. This research involved graduate student research that was their thesis or dissertation project. TARGET AUDIENCES: The target audience were growers with the ultimate benefit being to the U.S. consumers of these crops. By controlling pests such as weeds, better quality and more quantity of vegetables and fruits are available for consumers. In addition, our work in the IR-4 program at NC State University is part of the national IR-4 program which has contributed to the U.S. having the safest food source in the world. According to a recent report by the Center for Economic Analysis at Michigan State University, the IR-4 project contributes nearly $7.7 billion to the US Gross Domestic Product.

Impacts
Management programs involving metolachlor and flumioxazin herbicides for control of Palmer amaranth, a weed that threatens crop production in the southeastern U.S., were developed that provide good control of this weed. Growers have adapted much of this technology that was developed beginning in 2006. Palmer amaranth has the ability to grow over two inches per day, produce over 500,000 seeds per female plant and eliminate sweetpotato yield and quality. We participated in the development of the use pattern of the two herbicides halosulfuron and flumioxazin in blueberries. Registrations of these herbicides are expected in 2008 and 2009. Growers anticipate using these herbicides in their weed management program to control the most problematic broadleaf weeds and nutsedge. Two state local need registrations for paraquat and clethodim herbicides in clary sage were developed for North Carolina based on data developed from studies conducted onfarm for weed control. These registrations saved clary sage growers an estimated over 1 million dollars per year in North Carolina.

Publications

  • MacRae, A.W., W.E. Mitchem. and D.W. Monks. 2007. Tree growth, fruit size, and yield response of mature peach to weed-free intervals. Weed Tech. 21(1):102-105.
  • MacRae, A.W., D.W. Monks, R.B. Batts and A.C. Thornton. 2007. Sweetpotato tolerance to thifensulfuron applied postemergence. Weed Tech. 21(4):928-931.
  • A.W. MacRae, D.W. Monks, R.B. Batts, A.C. Thornton and J.R. Schultheis. 2007. Sweetpotato tolerance to halosulfuron applied postemergence. Weed Tech. 21(4):993-996.
  • Harrelson, E.R., G. Hoyt, J.L. Havlin, and D.W. Monks. 2007. Effect of winter cover crop residue on no-till pumpkin yield. HortScience 42(7): 1568-1574.


Progress 10/01/05 to 09/30/06

Outputs
Approximately 30 studies were conducted evaluating methods for controlling weeds in fruits and vegetable crops. In addition,residue trials involved 12 different specialty fruit and vegetable crops and 16 different pest control agents (6 herbicides, 6 insecticide/miticides, 1 plant growth regulator, and 3 fungicides) were also conducted to support the National IR-4 program for pesticide registration and re-registration. Research found that as few as 1 eastern black nightshade per 2 feet of row resulted in a reduction in value of tomato fruit (large, extra large and jumbo grade) indicating that growers must keep levels of this weed below 1 weed per 2 feet of row in plasticulture. In addition studies found that the critical weed free period was approximately 28 to 50 days after tomato transplanting indicating to growers that it is most important to control weeds during this period of time in tomato fields. Research with Sandea herbicide identified the timing that this herbicide could be applied in yellow squash. The preemergence application of Sandea was the safest application relative to postemergence application in squash.

Impacts
Research from our studies will be used to develop programs that growers can use to reduce the negative impact that weeds have on their crops. The public will benefit by this research as the fruits and vegetables that they consume will be higher quality and will improve the health of people who consume these crops. New pesticide registrations for vegetable and fruit crops will result from this project's cooperative research with the National IR-4 Program resulting in reduction of losses (millions of dollars) due to weeds.

Publications

  • Buckelew, J.K. and D.W. Monks. 2006. Effect of eastern black nightshade (Solanum ptycanthum) on transplanted plasticulture tomato grade and yield. Weed Sci. 54:504-508.
  • Buckelew, J.K., D.W. Monks, G.D. Hoyt and R.F. Walls. 2006. Eastern black nightshade (Solanum ptycanthum) reproduction and interference in transplanted plasticulture tomato. Weed Sci. 54:490-495.
  • Starke, K.D., D.W. Monks, W.E. Mitchem and A.W. MacRae. 2006. Response of five squash (Cucurbita pepo) to halosulfuron PRE and POST. Weed Tech. 20:617-621.


Progress 10/01/04 to 09/30/05

Outputs
Several studies were conducted to develop control programs in vegetable and fruit crops for some of the worst weeds in the world. Studies were focused primarily on various pigweeds (Palmer and spiny amaranths) and the nutsedges (purple and yellow). Several herbicides were identified in tomato, sweetpotato, watermelon, cantaloupe, pepper, snapbean, and potato that give effective control of the nutsedges. Pigweed control by various herbicides was poor to fair in most cases. Work will continue to identify methods for controlling pigweeds and other broadleaf weeds in vegetable crops. Weed management programs were also evaluated in grapes, peaches, and apples. Several progams included Chateau herbicide and gave long lasting effective weed control in these perennial crops. In addition, the IR-4 Research Center at NC State University which is under this project conducted 28 studies with 16 different pesticides (6 insecticides/miticides, 6 herbicides, 1 plant growth regulator, 3 fungicides)in 12 different crops. Data from this research will be used by the National IR-4 Program to develop pesticide registrations in these crops and many other specialty crops from the Environmental Protection Agency. The IR-4 Program continues to be critical in developing pesticide registrations for fruit and vegetable crops. In additon to this work, several natural herbicides are being evaluated in vegetable and fruit crops that could possibly be utilized by organic producers.

Impacts
Research from our studies will be used to develop programs that growers can use to reduce the negative impact that weeds have on their crops. The public will benefit by this research as the fruits and vegetables that they consume will be higher quality and will improve the health of people who consume these crops. New pesticide registrations for vegetable and fruit crops will result from this project's cooperative research with the National IR-4 Program resulting in reduction of losses (millions of dollars) due to weeds.

Publications

  • MacRae, A.W., Mitchem, W.E., Monks, D.W. and Parker, M.L. 2005. White clover control and flower head suppression in apple orchards. Weed Tech 19:219-223.


Progress 10/01/03 to 09/30/04

Outputs
Studies were conducted to determine the critical period for controlling eastern black nightshade in tomato grown on plastic mulch and the density at which eastern black nightshade reduces yield of tomato grown in this production system. Over two locations, either the premium grade of jumbo tomato fruit was reduced or the number 3 grade (blemished) fruit was increased by the presence of eastern black nightshade. In addition, eastern black nightshade was observed to overwinter as a perennial weed in plasticulture. In our studies, this weed could sprout and grow another shoot when cut at the soil surface, and the above ground shoot could reroot when it was removed and discarded to the ground. Studies were also conducted in apples, blueberries, cucurbits, onion, pepper, potato, strawberry, sweetpotato, tomato, and watermelon to identify herbicides that are effective and safe to these crops. In addition, alternatives to methyl bromide were also evaluated in cucurbit crops and tomato. Thus far, clopyralid (strawberry), oxyflourfen (tomato, pepper), metolachlor (sweetpotato, tomato) and halosulfuron (sweetpotato, tomato), and flumioxazin (sweetpotato) herbicides have shown promise.

Impacts
The impact from these studies will be to provide growers with alternatives for methyl bromide in tomato, pepper, and cucurbit crops resulting in less reductions in fruit yield and quality from weeds. Growers will also be able to control eastern black nightshade, a relative of tomato, in tomato grown on plastic. Results from the herbicide evaluation studies will be used to identify effective herbicides in each crop resulting in increased control of weeds that are currently reducing yield and quality of crops, and reducing harvest efficiency.

Publications

  • No publications reported this period