Progress 08/01/06 to 07/31/11
Outputs
OUTPUTS: The long-range goal of this research is to develop low-cost best management practices that improve the consistency and efficacy of weed suppressive soils. The objective was to determine the contribution of F. lateritium to weed suppressiveness and velvetleaf abundance. The central hypothesis was that F. lateritium is the primary cause of observed weed suppressiveness in soils in eastern Nebraska. We have shown that F. lateritium is a naturally occurring soil borne pathogen that has a deleterious effect on velvetleaf. While the indigenous population of F. lateritium was observed to develop over time as a negative plant-soil feedback, the pathogen can also be cultured and used to inoculate soils to become suppressive to velvetleaf. We developed inoculum for application in the field to quantify its effects on velvetleaf population biology and on natural weed populations in an organic crop rotation. We found that velvetleaf seedling emergence was reduced by inoculation with F. lateritium, but subsequent establishment of the pathogen in soils is environmentally dependent and not successful in the two years of our field research. Therefore, there was no effect of the organism on established velvetleaf plants or their impact on the maize crop. Subsequent research would be needed to develop management practices to naturally enhance the F. lateritium populations in soil rather than using an inundative approach with inoculum. This research may have the greatest potential to aid organic crop production practices. Results of this research have been disseminated to organic crop production groups in Nebraska as well as to scientists attending the American Phytopathological society, the Ecological Society of America, the North Central Weed Science Society, the Weed Science Society of America, and the American Society of Agronomy. PARTICIPANTS: Jane Okalebo was an M.S. student that conducted research to address objectives 1 and 2. Nabaraj Banjara is an M.S. student conducting the research to address objectives 3 and 4. Darren Binder is a research technologist that oversees the day to day management of all our research projects. Several undergraduate hourly employees have provided labor in the greenhouse and field during the reporting period. PI Yuen has provided the guidance on methodology in plant pathology to both graduate students. PI Lindquist provides overall guidance to all students and employees and manages the entire project. TARGET AUDIENCES: We believe that the primary target audience for this research is the organic crop production community. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This research is innovative because studies on the effects of naturally occurring soilborne fungal pathogens on weed competitiveness and population biology are limited. While our results suggest that utilizing F. lateritium as an inundative biological control agent (e. g. a bioherbicide), there remains the possibility of using alternative cultural practices to enhance the native F. lateritium populations in soil. This research could have great potential for managing velvetleaf and other weeds in organic crop production systems.
Publications
- Okalebo, J. A., J. L. Lindquist, G. Yuen, R. Drijber and E. Blankenship. 2007. Contribution of fungal pathogens to velvetleaf (Abutilon theophrasti) suppressiveness of eastern Nebraska soils. WSSA Abstracts 60:134. [Winner, Sigma Xi UNL Graduate Student Poster competition]
- Okalebo, J., J. Lindquist, G. Yuen and R. Drijber. 2006. Can soil become biologically suppressive to velvetleaf Proceedings of the North Central Weed Science Society 61:173.
- Okalebo, J., G. Y. Yuen, R. A. Drijber, E. E. Blankenship, C. Eken, and J. L. Lindquist. 2011. Biological suppression of velvetleaf (Abutilon theophrasti) in an eastern Nebraska soil. Weed Sci. 59:155-161.
- Okalebo, Jane. 2008. Biological suppression of velvetleaf (Abutilon theophrasti) in an eastern Nebraska soil. Master of Science thesis, University of Nebraska, Lincoln Nebraska.
- Banjara, N., J. L. Lindquist, G. Yuen and R. Drijber. 2010. Demography of velvetleaf in corn and soybean as influenced by Fusarium lateritium inoculation. Proceedings of the North Central Weed Science Society 65:64.
- Banjara, N., J. L. Lindquist and G. Yuen. 2008. Methods of culturing Fusarium lateritium. Proceedings of the North Central Weed Science Society 63:69.
- Okalebo, J. A., J. L. Lindquist, G. Y. Yuen, R. A. Drijber and E. E. Blankenship. 2008. The role of plant pathogens in suppressing growth and development of Abutilon theophrasti (velvetleaf) Phytopathology 98(6):204.
- Okalebo, J. A., J. L. Lindquist, G. Y. Yuen, R. A. Drijber and E. E. Blankenship. 2008. Can soil pathogenic fungi be used to suppress weedy plants in agroecosystems Ecological Society of America, Milwaukee, WI, August 3-8, 2008.
- Okalebo, J. A., J. L. Lindquist, G. Yuen, R. Drijber and E. Blankenship. 2007. Weed suppressive soils in eastern Nebraska. Agronomy Abstracts 152-5.
|
Progress 08/01/09 to 07/31/10
Outputs
OUTPUTS: The long-range goal of this research is to develop low-cost best management practices that improve the consistency and efficacy of weed suppressive soils. The objective was to determine the contribution of F. lateritium to weed suppressiveness and velvetleaf abundance. The central hypothesis was that F. lateritium is the primary cause of observed weed suppressiveness in soils in eastern Nebraska. To date, we have shown that F. lateritium is a naturally occurring soil borne pathogen that has a deleterious effect on velvetleaf. While the indigenous population of F. lateritium was observed to develop over time as a negative plant-soil feedback, the pathogen can also be cultured and used to inoculate soils to become suppressive to velvetleaf. We are in the process of using the inoculum to quantify its effects on velvetleaf population biology and on natural weed populations in an organic crop rotation. This research may have the greatest potential to aid organic crop production practices. Results of this research have been disseminated to organic crop production groups in Nebraska as well as to scientists attending the American Phytopathological society, the Ecological Society of America, the North Central Weed Science Society, the Weed Science Society of America, and the American Society of Agronomy. PARTICIPANTS: Jane Okalebo was an M.S. student that conducted research to address objectives 1 and 2. Nabaraj Banjara is an M.S. student conducting the research to address objectives 3 and 4. Darren Binder is a research technologist that oversees the day to day management of all our research projects. Several undergraduate hourly employees have provided labor in the greenhouse and field during the reporting period. PI Yuen has provided the guidance on methodology in plant pathology to both graduate students. PI Lindquist provides overall guidance to all students and employees and manages the entire project. TARGET AUDIENCES: From a practical standpoint, we believe that the primary target audience for this research is the organic crop production community. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This research is innovative because studies on the effects of naturally occurring soilborne fungal pathogens on weed competitiveness and population biology are limited. It is our expectation that results will indicate sufficient velvetleaf suppression to emphasize its utility in an integrated weed management program. In particular, we think that this research could have great potential for managing velvetleaf and other weeds in organic crop production systems.
Publications
- No publications reported this period
|
Progress 08/01/08 to 07/31/09
Outputs
OUTPUTS: The long-range goal of this research is to develop low-cost best management practices that improve the consistency and efficacy of weed suppressive soils. The objective was to determine the contribution of F. lateritium to weed suppressiveness and velvetleaf abundance. The central hypothesis was that F. lateritium is the primary cause of observed weed suppressiveness in soils in eastern Nebraska. To date, we have shown that F. lateritium is a naturally occurring soil borne pathogen that has a deleterious effect on velvetleaf. While the indigenous population of F. lateritium was observed to develop over time as a negative plant-soil feedback, the pathogen can also be cultured and used to inoculate soils to become suppressive to velvetleaf. We are in the process of using the inoculum to quantify its effects on velvetleaf population biology and on natural weed populations in an organic crop rotation. This research may have the greatest potential to aid organic crop production practices. Results of this research have been disseminated to organic crop production groups in Nebraska as well as to scientists attending the American Phytopathological society, the Ecological Society of America, and the North Central Weed Science Society. PARTICIPANTS: Jane Okalebo was an M.S. student that conducted research to address objectives 1 and 2. Nabaraj Banjara is an M.S. student conducting the research to address objectives 3 and 4. Darren Binder is a research technologist that oversees the day to day management of all our research projects. Several undergraduate hourly employees have provided labor in the greenhouse and field during the reporting period. PI Yuen has provided the guidance on methodology in plant pathology to both graduate students. PI Lindquist provides overall guidance to all students and employees and manages the entire project. TARGET AUDIENCES: From a practical standpoint, we believe that the primary target audience for this research is the organic crop production community. To begin outreach to this group, we presented a poster on the project at the annual meeting of the Nebraska Sustainable Agriculture Society in February 2009. PROJECT MODIFICATIONS: 2009 was the first year we were able to go to the field with this research to complete objectives 3 and 4. Unfortunately, in part because of a switch in students (Okalebo graduated and Banjara was getting up to speed in plant pathology methodology), one of our stored inoculum became contaminated. We did not know this until well after it was used to prepare a stock inoculum for the field work this summer. In short, we inoculated the field with the wrong species of Fusarium. This research will need to be repeated in 2010. We did complete the project with the wrong inoculum in 2009 and will do the velvetleaf demographic analysis as outlined in the proposal.
Impacts
This research is innovative because studies on the effects of naturally occurring soilborne fungal pathogens on weed competitiveness and population biology are limited. It is our expectation that results will indicate sufficient velvetleaf suppression to emphasize its utility in an integrated weed management program. In particular, we think that this research could have great potential for managing velvetleaf and other weeds in organic crop production systems.
Publications
- Banjara, N., J. L. Lindquist and G. Yuen. 2008. Methods of culturing Fusarium lateritium. Proceedings of the North Central Weed Science Society.
- Okalebo, J. A., J. L. Lindquist, G. Y. Yuen, R. A. Drijber and E. E. Blankenship. 2008. The role of plant pathogens in suppressing growth and development of Abutilon theophrasti (velvetleaf) Phytopathology 98(6):204.
- Okalebo, J. A., J. L. Lindquist, G. Y. Yuen, R. A. Drijber and E. E. Blankenship. 2008. Can soil pathogenic fungi be used to suppress weedy plants in agroecosystems Ecological Society of America.
|
Progress 08/01/07 to 07/31/08
Outputs
OUTPUTS: The long-range goal of this research is to develop low-cost best management practices that improve the consistency and efficacy of weed suppressive soils. The objective of the proposed research, which is the next step toward attaining that goal, is to determine the contribution of F. lateritium to weed suppressiveness and velvetleaf abundance. The central hypothesis is that F. lateritium is the primary cause of observed weed suppressiveness in soils in eastern Nebraska. This hypothesis was formulated on the basis of published literature describing F. lateritium as a destructive pathogen of velvetleaf, on our preliminary findings that F. lateritium infects velvetleaf in normally managed fields in eastern Nebraska, and that differential suppression of velvetleaf growth occurs among these fields. The rationale for the proposed research is that an understanding of the cause of weed suppressiveness in soils will facilitate the development of management practices to enhance that suppression. The proposed research directly contributes to establishing one causal factor in explaining the abundance and varying effects of velvetleaf in corn production systems. To date we have accomplished the first two of our four objectives and are making progress on the third and fourth: 1. Verify that the soil in fields observed to have reduced velvetleaf growth is biologically suppressive to velvetleaf. 2. Evaluate the contribution of F. lateritium to the velvetleaf suppressiveness of soils. 3. Quantify the effects of suppressive soils on velvetleaf population dynamics. 4. Compare predicted velvetleaf abundance and economic returns over time resulting from an F. lateritium infected and uninfected velvetleaf population in corn. A graduate student worked on the laboratory component of this research (objectives 1 and 2) and will defend in fall 2008. We have verified the biological suppressiveness of a soil encountered in our previous research in Nebraska, isolated F. lateritium from numerous velvetleaf plants expressing disease symptoms, and verified the pathogenicity of F. lateritium. We are currently evaluating the best method of culturing large quantities for the future inoculation of greenhouse and field soils. Posters on the research accomplished to date were presented at annual meetings of the North Central Weed Science Society, Weed Science Society of America, and American Pytopathological Society, and Ecological Society of America. A manuscript on the work accomplished so far will be submitted in fall 2008. A second graduate student was recruited to work on the greenhouse and field aspects of this project (objectives 3 and 4). PARTICIPANTS: Dr. Cafer Eken worked as a temporary postdoctoral scientist on the project, assisting with plant collection in the field and subsequent evaluation of the frequency of occurrence of several potential pathogens responsible for suppressiveness. Jane Okalebo is a M.S. student who completed much of the research on Objectives 1 and 2. She will defend her thesis in September, 2008. Nabaraj Banjara is a M.S. student working on objective 3. TARGET AUDIENCES: Target audiences include agricultural producers in Nebraska and throughout the corn production regions of the United States. Results of this research will be of particular interest to organic or low input producers. Extension efforts will focus on the sustainable agriculture community. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This research is innovative because studies on the effects of naturally occurring soilborne fungal pathogens on weed competitiveness and population biology are limited. It is our expectation that results will indicate sufficient velvetleaf suppression to emphasize its utility in an integrated weed management program.
Publications
- No publications reported this period
|
Progress 08/01/06 to 07/31/07
Outputs
The long-range goal of this research is to develop low-cost best management practices that improve the consistency and efficacy of weed suppressive soils. The objective of the proposed research, which is the next step toward attaining that goal, is to determine the contribution of F. lateritium to weed suppressiveness and velvetleaf abundance. The central hypothesis is that F. lateritium is the primary cause of observed weed suppressiveness in soils in eastern Nebraska. This hypothesis was formulated on the basis of published literature describing F. lateritium as a destructive pathogen of velvetleaf, on our preliminary findings that F. lateritium infects velvetleaf in normally managed fields in eastern Nebraska, and that differential suppression of velvetleaf growth occurs among these fields. The rationale for the proposed research is that an understanding of the cause of weed suppressiveness in soils will facilitate the development of management practices to enhance
that suppression. The proposed research directly contributes to establishing one causal factor in explaining the abundance and varying effects of velvetleaf in corn production systems. In the first year of this project we have accomplished the first of our four objectives and are making strong headway on the second: 1. Verify that the soil in fields observed to have reduced velvetleaf growth is biologically suppressive to velvetleaf. 2. Evaluate the contribution of F. lateritium to the velvetleaf suppressiveness of soils. 3. Quantify the effects of suppressive soils on velvetleaf population dynamics. 4. Compare predicted velvetleaf abundance and economic returns over time resulting from an F. lateritium infected and uninfected velvetleaf population in corn. A graduate student was recruited to work on the laboratory component of this research (objectives 1 and 2). We have verified the biological suppressiveness of a soil encountered in our previous research in Nebraska and have
isolated F. lateritium from numerous velvetleaf plants expressing disease symptoms. We are currently verifying the pathogenicity of F. lateritium and evaluating the best method of culturing large quantities for the future inoculation of greenhouse and field soils. Posters on the research accomplished to date were presented at annual meetings of the North Central Weed Science Society, Weed Science Society of America, and American Pytopathological Society. A manuscript on the work accomplished so far is in progress. We are currently recruiting a second graduate student to work on the greenhouse and field aspects of this project (objectives 3 and 4), which will be initiated in summer 2008.
Impacts
This research is innovative because studies on the effects of naturally occurring soilborne fungal pathogens on weed competitiveness and population biology are limited. It is our expectation that results will indicate sufficient velvetleaf suppression to emphasize its utility in an integrated weed management program.
Publications
- No publications reported this period
|
|