Progress 03/15/17 to 02/17/21
Outputs
Target Audience:Target audiences include researchers and students at different universities in the U.S., sunflower farmers (which includes those serving as the directors of the National Sunflower Association and the South Dakota Oilseed Council), agriculture professionals working on sunflowers (e.g. crop consultants), and the community-at-large. Efforts include presentation of research at scientific and extension meetings, training industry personnel (e.g. Nuseed) and growers on diagnosis of Phomopsis stem canker, and how to manage the disease using fungicides. Changes/Problems:For 2020-2021, because of the CoVID19 pandemic and resulting travel restrictions, the scientific and extension events that were to be held in person were converted to virtual meetings. What opportunities for training and professional development has the project provided?In South Dakota, three Ph.D. students (Mr. Renan Guidini, Ms. Ruchika Kashyap and Mr. Nabin Dangal) and two research staff members (Mr. Nathan Braun and Mr. Brian Kontz) were trained in diagnosis of Phomopsis stem canker, fungal inoculations in the greenhouse, statistical analyses, and development and validation of a prediction model to forecast disease outbreak. In addition, all personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at meetings of the following: American Phytopathological Society, Mycological Society of American, the Annual Sunflower Research Forum, Great Plains Diagnostic Network, and Northeastern Plant, Pest, and Soils Conference. In North Dakota, one graduate student (M.S.) (Mr. Bryan Hansen) and one research staff member (Ms. Jessica Halvorson) were trained in diagnosis of Phomopsis stem canker of sunflower, statistical analyses, and in the validation of prediction model to forecast disease outbreak and spray fungicides. In addition, all the above personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at the National Sunflower Association Annual Research Forum. In Nebraska, one undergraduate student (Ms. Allison Rickey) and two research staff members (Mr. Clay Carlson and Mr. Tyler Patrick) were trained in diagnosis of Phomopsis stem canker of sunflower. In addition, all the above personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at the National Sunflower Association Annual Research Forum. How have the results been disseminated to communities of interest?Results was shared through presentations at scientific and farmer-based meetings, extension and outreach events, press releases through SDSU, NDSU and UNL, and interviews (as listed under "Products"). What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objective 1: Examine the weather variables and develop SPRM to predict the development of Phomopsis stem canker of sunflower (100% Accomplished) To develop regression models, weather data including air temperature (C), relative humidity (%), rainfall (mm), wind speed (m/s), solar radiation (W/m2), and leaf wetness (0 or 1) were converted to moving averages. The disease severity data from field trials in Minnesota, North Dakota, and South Dakota in 2014, 2015, 2016 and 2017 were converted to binary variables and a model was developed using SAS PROC LOGISTIC (v. 9.4; SAS Institute, Cary, NC). All predictor variables were included in the initial analysis using stepwise, forward, backward, and score-selection methods. Models were evaluated for accuracy by performing a goodness-of-fit test in LACKFIT analysis in PROC LOGISTIC. The model with the highest accuracy was then validated with an independent data set which was not used to develop the logistic regression model. This independent data set consisted of 12 locations-years from Minnesota, North Dakota and South Dakota. The best model was developed using nine location-years and is given by the equation , where temperature (TMP), number of hours with relative humidity over 70% (RLH70), wind speed (WSP), and solar radiation (SRS) are the weather variables. Nine location-year datasets with daily observations were used to validate the selected model. These datasets were not previously used to develop the model. The model possessed excellent discrimination, with 0.66 max-rescaled R2 values and a high predicted model accuracy of 78%. Based on a probability value at which sensitivity and specificity converged, a disease probability threshold of 0.40 was used to determine model success or failure. For each validation site, the probability of disease occurrence was calculated by back-transforming from . The model predicted high (0.40 to 1.0), moderate (0.20 to 0.39) and low (0.01 to 0.19) risk of Phomopsis stem canker occurring at growth stage R1. When the forecasting model was validated, the model correctly predicted the severity of Phomopsis stem canker in 100% of the cases (sensitivity) and no disease in 92% of the cases (specificity). The risk map was uploaded onto iPIPE. Impact -The model was able to explain Phomopsis stem canker severity observed at reproductive stages of the sunflower plants. Objective 2: Validate SPRM under field conditions and determine the timing of fungicide applications. (100% Accomplished) Fungicide trials were established at five locations in three states (Nebraska, North Dakota, and South Dakota) in 2019. In North Dakota, the trials were established at the NDSU Research Farm (Carrington, ND) and with BASF (Davenport, ND). In South Dakota the trials were established at the SDSU Research Farms in Brookings and Volga. In North Dakota and South Dakota, the disease was evaluated under natural disease pressure. In Nebraska, the disease was introduced through Phomopsis-infested sunflower stalks that were spread between rows at the farm in Panhandle Research and Extension Center, Scottsbluff, NE. The study was a randomized complete block design with a split-plot arrangement of 11 total treatments. Two sunflower varieties were set at the whole plot level: susceptible (CHS = RH400CL, Mycogen = N4HM354) and moderately resistant (CHS = Experimental line, Mycogen = Camaro II). A labeled sunflower fungicide (Headline) was used at different growth stages: non-treated control, V8 (late vegetative), R1-R3 (miniature floral head development), R5 (flowering), V8+ R1, V8+ R5, R1+ R5, and V8 + R1 + R5. The remaining three treatments (one application of fungicide, two applications of fungicide, and three applications of fungicide) were applied to validate prediction model using the iPIPE risk map. We determined that besides weather variables, there are other factors that affect development of Phomopsis stem canker in sunflower. These factors include number of years since previous sunflower crop, number of Phomopsis-infected plants in previous sunflower crop, if sunflower is planted under irrigated conditions, and if Phomopsis stem canker was observed in the last five years. These were categorized as risk factors. Depending on these risk factors and whether the model predicted a disease probability > 0.40, fungicide applications were made at four locations. At the end of the season, disease severity was evaluated at growth stage R6-R8 (after flowering) using a 0-4 scale, where 0 = no infection, 1 = stem lesion < 2 inches, 2 = stem lesion > 2 inches, 3 = girdling stem lesion, and 4 = lodged plant. The rating scale was converted into disease severity index, which was calculated using the formula DSI (%) = ∑ {[(P x Q) / (M x N)] x 100} where P = disease severity rating, Q = number of infected plants having the same disease severity rating, M = total number of plants, N = maximum number on the disease severity rating scale. The disease severity index (DSI) and yield (obtained at the end of the season) will be analyzed in R (v2.11.1; https://www.rstudio.com/). Overall results Trials conducted in Nebraska, North Dakota and South Dakota showed that FRAC 11 fungicides were most effective against Phomopsis stem canker, and a single application of pyraclostrobin at R1 growth stage significantly reduced the disease severity (by 37.2%) and increased yield (by 5.6%) compared to the plots where the fungicide was not sprayed. However, the fungicide efficacy can vary depending on the disease pressure and weather conditions. Impact -Based on our research, farmers would see yield benefits (200 to 600 lbs/A increase) when sunflower hybrids are sprayed at R1 growth stage against Phomopsis stem canker. Objective 3: Deliver SPRM to sunflower farmers and other stakeholders through extension and education activities. (100% Accomplished) Results have been shared through presentations at the annual sunflower forum organized by the National Sunflower Association for the farmers and sunflower industry organized in 2021. Impact -Sunflower farmers in Minnesota, Nebraska, North Dakota, and South Dakota were educated on spraying fungicides (Headline or other QoI containing products) at the R1 growth stage to manage Phomopsis stem canker.
Publications
- Type:
Other
Status:
Other
Year Published:
2021
Citation:
Kashyap, R., and Mathew, F. 2021. Evaluating sensitivity of sunflower fungi, Diaporthe helianthi and D. gulyae, to pyraclostrobin (QoI) fungicide. GPDN Webinar Series for 2021. (Virtual). January 27.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
Dangal, N., Markell, S., Harveson, B., and Mathew, F. 2021. Diversity of endophytic Phomopsis and other fungi in sunflower. Proceedings of the 42nd Annual Sunflower Research Forum. (Virtual). January 13-14.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
Guidini, R., Braun, N., Chang, J., and Mathew, F. 2021. Evaluation of fungicides for their efficacy against Phomopsis stem canker of sunflower using remote sensing. Proceedings of the 42nd Annual Sunflower Research Forum. Virtual. January 13-14.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
Kashyap, R., Underwood, W., Markell, S., Harveson, B., and Mathew, F. 2021. Evaluation of sensitivity of D. helianthi and D. gulyae to pyraclostrobin (QoI, FRAC 11) fungicide under lab conditions. Proceedings of the 42nd Annual Sunflower Research Forum. Virtual. January 13-14.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
Kashyap, R., Kontz, B., Underwood, W., Markell, S., Harveson, B., and Mathew, F. 2021. Sensitivity of Diaporthe helianthi and D. gulyae causing Phomopsis stem canker of sunflower to tebuconazole fungicide. Proceedings of the Northeastern Plant, Pest, and Soils Conference. Virtual. January 4-7.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Mathew, F.M., Markell, S., and Harveson, R. 2020. Analyzing yield response to application of pyraclostrobin in sunflower (Helianthus annuus L.). 41st Annual meeting of the Plant Pathology society of Alberta, Canada. Virtual. November 4-5.
- Type:
Other
Status:
Other
Year Published:
2020
Citation:
Mathew, F., Markell, S., and Harveson, R. 2020. Phomopsis stem canker in sunflower - Update on fungicide research and use recommendations. The Sunflower; Published August 2020.
- Type:
Book Chapters
Status:
Other
Year Published:
2020
Citation:
Markell, S., Mathew, F., and Harveson, R. 2020. Diseases of sunflower. Sunflower Production Guide. NDSU Extension Service.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Braun, N., Moradi, H., Markell, S., Harveson, R., Harfield, G., Carlson, C., Hansen, B., Halvorson, J., Patrick, T., Rickey, A., and Mathew, F.M. 2020. Determining yield response to foliar fungicide application in sunflower (Helianthus annuus L.). American Phytopathological Society Annual Meeting. Virtual. August 8-12.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Dangal, N.K., Markell, S.G., Harveson, R.M., Braun, N., Carlson, C., Hansen, B., Halvorson, J., Kontz, B., Patrick, T., Rickey, A., and Mathew, F.M. 2020. Species of Diaporthe can survive as endophytes on sunflower. Mycological Society of America Annual Meeting. Virtual. July 21-22.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Mathew, F. 2020. Sunflower diseases. Webinar, Research Extension Centers Carrington and Dickinson, North Dakota State University, Fargo, ND. Virtual. March 4.
|
Progress 03/15/17 to 02/02/21
Outputs
Target Audience:Target audiences include researchers and students at different universities in the U.S., sunflower farmers (which includes those serving as the directors of the National Sunflower Association and the South Dakota Oilseed Council), agriculture professionals working on sunflowers (e.g. crop consultants), and the community-at-large. Efforts include presentation of research at scientific and extension meetings, training industry personnel (e.g. Nuseed) and growers on diagnosis of Phomopsis stem canker, and how to manage the disease using fungicides. Changes/Problems:For 2020-2021, because of the CoVID19 pandemic and resulting travel restrictions, the scientific and extension events that were to be held in person were converted to virtual meetings. What opportunities for training and professional development has the project provided?In South Dakota, three Ph.D. students (Mr. Renan Guidini, Ms. Ruchika Kashyap and Mr. Nabin Dangal) and two research staff members (Mr. Nathan Braun and Mr. Brian Kontz) were trained in diagnosis of Phomopsis stem canker, fungal inoculations in the greenhouse, statistical analyses, and development and validation of a prediction model to forecast disease outbreak. In addition, all personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at meetings of the following: American Phytopathological Society, Mycological Society of American, the Annual Sunflower Research Forum, Great Plains Diagnostic Network, and Northeastern Plant, Pest, and Soils Conference. In North Dakota, one graduate student (M.S.) (Mr. Bryan Hansen) and one research staff member (Ms. Jessica Halvorson) were trained in diagnosis of Phomopsis stem canker of sunflower, statistical analyses, and in the validation of prediction model to forecast disease outbreak and spray fungicides. In addition, all the above personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at the National Sunflower Association Annual Research Forum. In Nebraska, one undergraduate student (Ms. Allison Rickey) and two research staff members (Mr. Clay Carlson and Mr. Tyler Patrick) were trained in diagnosis of Phomopsis stem canker of sunflower. In addition, all the above personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at the National Sunflower Association Annual Research Forum. How have the results been disseminated to communities of interest?Results was shared through presentations at scientific and farmer-based meetings, extension and outreach events, press releases through SDSU, NDSU and UNL, and interviews (as listed under "Products"). What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objective 1: Examine the weather variables and develop SPRM to predict the development of Phomopsis stem canker of sunflower (100% Accomplished) To develop regression models, weather data including air temperature (C), relative humidity (%), rainfall (mm), wind speed (m/s), solar radiation (W/m2), and leaf wetness (0 or 1) were converted to moving averages. The disease severity data from field trials in Minnesota, North Dakota, and South Dakota in 2014, 2015, 2016 and 2017 were converted to binary variables and a model was developed using SAS PROC LOGISTIC (v. 9.4; SAS Institute, Cary, NC). All predictor variables were included in the initial analysis using stepwise, forward, backward, and score-selection methods. Models were evaluated for accuracy by performing a goodness-of-fit test in LACKFIT analysis in PROC LOGISTIC. The model with the highest accuracy was then validated with an independent data set which was not used to develop the logistic regression model. This independent data set consisted of 12 locations-years from Minnesota, North Dakota and South Dakota. The best model was developed using nine location-years and is given by the equation , where temperature (TMP), number of hours with relative humidity over 70% (RLH70), wind speed (WSP), and solar radiation (SRS) are the weather variables. Nine location-year datasets with daily observations were used to validate the selected model. These datasets were not previously used to develop the model. The model possessed excellent discrimination, with 0.66 max-rescaled R2 values and a high predicted model accuracy of 78%. Based on a probability value at which sensitivity and specificity converged, a disease probability threshold of 0.40 was used to determine model success or failure. For each validation site, the probability of disease occurrence was calculated by back-transforming from . The model predicted high (0.40 to 1.0), moderate (0.20 to 0.39) and low (0.01 to 0.19) risk of Phomopsis stem canker occurring at growth stage R1. When the forecasting model was validated, the model correctly predicted the severity of Phomopsis stem canker in 100% of the cases (sensitivity) and no disease in 92% of the cases (specificity). The risk map was uploaded onto iPIPE. Impact -The model was able to explain Phomopsis stem canker severity observed at reproductive stages of the sunflower plants. Objective 2: Validate SPRM under field conditions and determine the timing of fungicide applications. (100% Accomplished) Fungicide trials were established at five locations in three states (Nebraska, North Dakota, and South Dakota) in 2019. In North Dakota, the trials were established at the NDSU Research Farm (Carrington, ND) and with BASF (Davenport, ND). In South Dakota the trials were established at the SDSU Research Farms in Brookings and Volga. In North Dakota and South Dakota, the disease was evaluated under natural disease pressure. In Nebraska, the disease was introduced through Phomopsis-infested sunflower stalks that were spread between rows at the farm in Panhandle Research and Extension Center, Scottsbluff, NE. The study was a randomized complete block design with a split-plot arrangement of 11 total treatments. Two sunflower varieties were set at the whole plot level: susceptible (CHS = RH400CL, Mycogen = N4HM354) and moderately resistant (CHS = Experimental line, Mycogen = Camaro II). A labeled sunflower fungicide (Headline) was used at different growth stages: non-treated control, V8 (late vegetative), R1-R3 (miniature floral head development), R5 (flowering), V8+ R1, V8+ R5, R1+ R5, and V8 + R1 + R5. The remaining three treatments (one application of fungicide, two applications of fungicide, and three applications of fungicide) were applied to validate prediction model using the iPIPE risk map. We determined that besides weather variables, there are other factors that affect development of Phomopsis stem canker in sunflower. These factors include number of years since previous sunflower crop, number of Phomopsis-infected plants in previous sunflower crop, if sunflower is planted under irrigated conditions, and if Phomopsis stem canker was observed in the last five years. These were categorized as risk factors. Depending on these risk factors and whether the model predicted a disease probability > 0.40, fungicide applications were made at four locations. At the end of the season, disease severity was evaluated at growth stage R6-R8 (after flowering) using a 0-4 scale, where 0 = no infection, 1 = stem lesion < 2 inches, 2 = stem lesion > 2 inches, 3 = girdling stem lesion, and 4 = lodged plant. The rating scale was converted into disease severity index, which was calculated using the formula DSI (%) = ∑ {[(P x Q) / (M x N)] x 100} where P = disease severity rating, Q = number of infected plants having the same disease severity rating, M = total number of plants, N = maximum number on the disease severity rating scale. The disease severity index (DSI) and yield (obtained at the end of the season) will be analyzed in R (v2.11.1; https://www.rstudio.com/). Overall results Trials conducted in Nebraska, North Dakota and South Dakota showed that FRAC 11 fungicides were most effective against Phomopsis stem canker, and a single application of pyraclostrobin at R1 growth stage significantly reduced the disease severity (by 37.2%) and increased yield (by 5.6%) compared to the plots where the fungicide was not sprayed. However, the fungicide efficacy can vary depending on the disease pressure and weather conditions. Impact -Based on our research, farmers would see yield benefits (200 to 600 lbs/A increase) when sunflower hybrids are sprayed at R1 growth stage against Phomopsis stem canker. Objective 3: Deliver SPRM to sunflower farmers and other stakeholders through extension and education activities. (100% Accomplished) Results have been shared through presentations at the annual sunflower forum organized by the National Sunflower Association for the farmers and sunflower industry organized in 2021. Impact -Sunflower farmers in Minnesota, Nebraska, North Dakota, and South Dakota were educated on spraying fungicides (Headline or other QoI containing products) at the R1 growth stage to manage Phomopsis stem canker.
Publications
- Type:
Other
Status:
Other
Year Published:
2021
Citation:
Kashyap, R., and Mathew, F. 2021. Evaluating sensitivity of sunflower fungi, Diaporthe helianthi and D. gulyae, to pyraclostrobin (QoI) fungicide. GPDN Webinar Series for 2021. (Virtual). January 27.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
Dangal, N., Markell, S., Harveson, B., and Mathew, F. 2021. Diversity of endophytic Phomopsis and other fungi in sunflower. Proceedings of the 42nd Annual Sunflower Research Forum. (Virtual). January 13-14.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
Guidini, R., Braun, N., Chang, J., and Mathew, F. 2021. Evaluation of fungicides for their efficacy against Phomopsis stem canker of sunflower using remote sensing. Proceedings of the 42nd Annual Sunflower Research Forum. Virtual. January 13-14.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
Kashyap, R., Underwood, W., Markell, S., Harveson, B., and Mathew, F. 2021. Evaluation of sensitivity of D. helianthi and D. gulyae to pyraclostrobin (QoI, FRAC 11) fungicide under lab conditions. Proceedings of the 42nd Annual Sunflower Research Forum. Virtual. January 13-14.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2021
Citation:
Kashyap, R., Kontz, B., Underwood, W., Markell, S., Harveson, B., and Mathew, F. 2021. Sensitivity of Diaporthe helianthi and D. gulyae causing Phomopsis stem canker of sunflower to tebuconazole fungicide. Proceedings of the Northeastern Plant, Pest, and Soils Conference. Virtual. January 4-7.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Mathew, F.M., Markell, S., and Harveson, R. 2020. Analyzing yield response to application of pyraclostrobin in sunflower (Helianthus annuus L.). 41st Annual meeting of the Plant Pathology society of Alberta, Canada. Virtual. November 4-5.
- Type:
Other
Status:
Other
Year Published:
2020
Citation:
Mathew, F., Markell, S., and Harveson, R. 2020. Phomopsis stem canker in sunflower - Update on fungicide research and use recommendations. The Sunflower; Published August 2020.
- Type:
Book Chapters
Status:
Other
Year Published:
2020
Citation:
Markell, S., Mathew, F., and Harveson, R. 2020. Diseases of sunflower. Sunflower Production Guide. NDSU Extension Service.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Braun, N., Moradi, H., Markell, S., Harveson, R., Harfield, G., Carlson, C., Hansen, B., Halvorson, J., Patrick, T., Rickey, A., and Mathew, F.M. 2020. Determining yield response to foliar fungicide application in sunflower (Helianthus annuus L.). American Phytopathological Society Annual Meeting. Virtual. August 8-12.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Dangal, N.K., Markell, S.G., Harveson, R.M., Braun, N., Carlson, C., Hansen, B., Halvorson, J., Kontz, B., Patrick, T., Rickey, A., and Mathew, F.M. 2020. Species of Diaporthe can survive as endophytes on sunflower. Mycological Society of America Annual Meeting. Virtual. July 21-22.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Mathew, F. 2020. Sunflower diseases. Webinar, Research Extension Centers Carrington and Dickinson, North Dakota State University, Fargo, ND. Virtual. March 4.
|
Progress 03/15/19 to 03/14/20
Outputs
Target Audience:Target audiences include researchers and students at different universities in the U.S., sunflower farmers (which includes those serving as the directors of the National Sunflower Association and the South Dakota Oilseed Council), agriculture professionals working on sunflowers (e.g. crop consultants), and the community-at-large. Efforts include presentation of research at scientific and extension meetings, training industry personnel (e.g. Nuseed) and growers on diagnosis of Phomopsis stem canker and how to manage the disease using fungicides. Changes/Problems:For 2019, we observed unexpected outcomes in our project - Overall, weather conditions did not favor development of Phomopsis stem canker at locations in North Dakota (Davenport and Carrington) in 2019 despite that spore traps were used to monitor the inocula of fungal pathogens causing Phomopsis stem canker of sunflower. The state suffered a near absence of rainfall that is critical for disease development. In Nebraska, the trial was damaged by four hail storms in 2019. We did not have access to the weather data to run the prediction model via the Integrated Pest Information Platform for Extension and Education (http://ed.ipipe.org/) because of logistics issues. As a result, the prediction model was done by hand using weather data from Mesonet (SDSU and UNL) and NDAWN (NDSU). Also, the SPRM map could not be uploaded onto the website of the National Sunflower Association. Regardless, we saw that spraying fungicides (specifically QoIs) at R1 growth stage delivered greater yield (≥ 100 lb/A), and hence we educated farmers in Minnesota, Nebraska, North Dakota and South Dakota concerning the practice of spraying fungicides (Headline or other QoI containing products) at R1 growth stage to manage Phomopsis stem canker. What opportunities for training and professional development has the project provided?In South Dakota, three undergraduate students (Mr. Mammen Korah, Mr. Glody Mbaki, and Ms. Janki Patel), one graduate student (M.S.) (Mr. Renan Guidini) and two research staff members (Mr. Nathan Braun and Mr. Brian Kontz) who are partially funded by this grant, were trained in diagnosis of Phomopsis stem canker, fungal inoculations in the greenhouse, statistical analyses, and development and validation of a prediction model to forecast disease outbreak. In addition, all the above personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at the American Phytopathological meetings (Annual and North-Central), the International Integrated Pest Management Symposium, the National Sunflower Association Annual Research Forum, and American Society of Agronomy (Annual). In North Dakota, one graduate student (M.S.) (Mr. Bryan Hansen) and two research staff members (Ms. Michelle Gilley and Ms. Jessica Halvorson) who are partially funded by this grant, were trained in diagnosis of Phomopsis stem canker of sunflower, statistical analyses, and in the validation of prediction model to forecast disease outbreak and spray fungicides. In addition, all the above personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at the American Phytopathological meetings (Annual and North-Central) and the National Sunflower Association Annual Research Forum. In Nebraska, one undergraduate student (Ms. Allison Rickey) and two research staff members (Mr. Clay Carlson and Mr. Tyler Patrick) who are partially funded by this grant, were trained in diagnosis of Phomopsis stem canker of sunflower. In addition, all the above personnel were given opportunities to present this research and other topics related to Phomopsis stem canker at the American Phytopathological meetings (Annual and North-Central), and the National Sunflower Association Annual Research Forum. How have the results been disseminated to communities of interest?Results have been shared through one peer reviewed publication, presentations at scientific and farmer-based meetings, extension and outreach events, press releases through SDSU, NDSU and UNL, and interviews (as listed under "Products"). What do you plan to do during the next reporting period to accomplish the goals?Objective 1. To examine the weather variables and develop a Sunflower Phomopsis Risk Map (SPRM) to predict the development of Phomopsis stem canker of sunflower. Nothing to Report: ________X_________ Objective 2. To validate SPRM under field conditions and determine the timing of fungicide applications. Nothing to Report: ________X_________ Objective 3. To deliver SPRM to sunflower farmers and other stakeholders through extension and education activities. Copies of the Sunflower Disease Diagnostic Series will be made available to farmers and stakeholders in the sunflower producing states of the United States.
Impacts
What was accomplished under these goals?
Objective 1: Examine the weather variables and develop SPRM to predict the development of Phomopsis stem canker of sunflower (100% Accomplished) To develop regression models, weather data including air temperature (C), relative humidity (%), rainfall (mm), wind speed (m/s), solar radiation (W/m2), and leaf wetness (0 or 1) were converted to 14-day moving averages. The disease assessment data from field trials in Minnesota, North Dakota, and South Dakota in 2014, 2015, 2016 and 2017 was converted to binary variables and a model was developed using SAS PROC LOGISTIC (v. 9.4; SAS Institute, Cary, NC). All predictor variables were included in the initial analysis using stepwise, forward, backward, and score-selection methods. Models were evaluated for accuracy by performing a goodness-of-fit test in LACKFIT analysis in PROC LOGISTIC. The model with the highest accuracy was then validated with an independent data set which was not used to develop the logistic regression model. This independent data set consisted of 12 locations-years from South Dakota, North Dakota, and Minnesota. The best model was developed using nine location-years and is given by the equation , where temperature (TMP), number of hours with relative humidity over 70% (RLH70), wind speed (WSP), and solar radiation (SRS) are the weather variables. Nine location-year datasets with daily observations were used to validate the selected model. These datasets were not previously used to develop the model. The model possessed excellent discrimination, with 0.66 max-rescaled R2 values and high predicted model accuracy of 78%. Based on a probability value at which sensitivity and specificity converged, a disease probability threshold of 0.40 was used to determine model success or failure. For each validation site, as well as total, the probability of disease occurrence was calculated by back-transforming from . The model predicted high (0.40 to 1), moderate (0.20 to 0.39) and low (0.01 to 0.19) risk of Phomopsis stem canker occurring at growth stage R1. When the forecasting model was validated, the model correctly predicted the severity of Phomopsis stem canker in 100% of the cases (sensitivity) and no disease in 92% of the cases (specificity). The risk map was uploaded onto iPIPE. Impact -The model was able to explain Phomopsis stem canker severity observed at reproductive stages of the sunflower plants. Objective 2: Validate SPRM under field conditions and determine the timing of fungicide applications. (100% Accomplished) Fungicide trials were established at five locations in three states (Nebraska, North Dakota, and South Dakota) in 2019. In North Dakota, the trials were established at the NDSU Research Farm (Carrington, ND) and with BASF (Davenport, ND). In South Dakota the trials were established at the SDSU Research Farms in Brookings and Volga. In North Dakota and South Dakota, the disease was evaluated under natural disease pressure. In Nebraska, the disease was introduced through Phomopsis-infested sunflower stalks that were spread between rows. The study was a randomized complete block design with a split-plot arrangement of 11 total treatments. Two sunflower varieties were set at the whole plot level: susceptible (CHS = RH400CL, Mycogen = N4HM354) and moderately resistant (CHS = Experimental line, Mycogen = Camaro II). A labeled sunflower fungicide (Headline) was used at different growth stages: non-treated control, V8 (late vegetative), R1-R3 (miniature floral head development), R5 (flowering), V8+ R1, V8+ R5, R1+ R5, and V8 + R1 + R5. The remaining three treatments (one application of fungicide, two applications of fungicide and three applications of fungicide) were applied to validate prediction model using the iPIPE risk map. We determined that besides weather variables, there are other factors that affect development of Phomopsis stem canker in sunflower. These factors include number of years since previous sunflower crop, number of Phomopsis-infected plants in previous sunflower crop, if sunflower is planted under irrigated conditions, and if Phomopsis stem canker was observed in the last five years. These were categorized as risk factors. Depending on these risk factors and whether the model predicted a disease probability > 0.40, fungicide applications were made at four locations. At the end of the season, disease severity was evaluated at growth stage R6-R8 (after flowering) using a 0-4 scale, where 0 = no infection, 1 = stem lesion < 2 inches, 2 = stem lesion > 2 inches, 3 = girdling stem lesion, and 4 = lodged plant. The rating scale was converted into disease severity index, which was calculated using the formula DSI (%) = ∑ {[(P x Q) / (M x N)] x 100} where P = disease severity rating, Q = number of infected plants having the same disease severity rating, M = total number of plants, N = maximum number on the disease severity rating scale. The disease severity index (DSI) and yield (obtained at the end of the season) will be analyzed in R (v2.11.1; https://www.rstudio.com/). Results for Year 3 Nebraska: In 2019, although the field trial was planted, the trial was damaged by four hail storms in the region because of which there is no data available. South Dakota: In 2019, we again did not observe significant differences in yield or disease severity index among the fungicide treatments for susceptible or partially resistant hybrids. However we did observe that Headline sprayed at the R1 growth stage gave greater yield (≥ 600 lb/A increase) than when the fungicide was not sprayed at all. North Dakota: No Phomopsis stem canker was observed in the trials in 2019. Impact -In 2019, greater yield (at least 100 lb/A increase) was observed for sunflower hybrids when fungicides were sprayed based on the model prediction or at R1 growth stage when compared to plants not sprayed with fungicides at all. Objective 3: Deliver SPRM to sunflower farmers and other stakeholders through extension and education activities. (80% Accomplished) Results have been shared through presentations at the Board of Directors meeting of the National Sunflower Association and the South Dakota Oilseed Council, as well as at the farmers meeting organized by the National Sunflower Association (Annual Research Forum in 2020). Impact -Sunflower farmers in Minnesota, Nebraska, North Dakota, and South Dakota were educated on spraying fungicides (Headline or other QoI containing products) at the R1 growth stage or using the prediction model to manage Phomopsis stem canker.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Dangal, N., Kontz, B., Braun, N., Markell, S., Harveson, R., and Mathew, F. 2020. Isolation and pathogenicity of Phomopsis from symptomless sunflower. 42nd National Sunflower Association Annual Research Forum, Fargo, ND. January 7-8.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Mathew, F., Harveson, R., Braun, N., Hansen, B., Halvorson, J., Carlson, C., Patrick, T., and Markell, S. 2020. Comparing R1 growth stage and prediction model based fungicide application to manage Phomopsis stem canker of sunflower. 42nd National Sunflower Association Annual Research Forum, Fargo, ND. January 7-8.
- Type:
Other
Status:
Accepted
Year Published:
2020
Citation:
Elverson, T. R., Kontz, B. J., Markell, S. G., Harveson, R. M., and Mathew, F. M. 2020. Quantitative polymerase chain reaction assays developed for Diaporthe helianthi and D. gulyae for Phomopsis stem canker diagnosis and germplasm screening in sunflower (Helianthus annuus). Plant Dis. https://doi.org/10.1094/PDIS-09-19-1827-RE.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
Guidini, R., Markell, S., Harveson, R., Johnson, M., Magarey, R., Isard, S., Braun, N., Carlson, C., Gilley, M., Hansen, B., Halvorson, J., Patrick, T., Rickey, A., and Mathew, F. 2019. Comparing growth stage and forecasting model based fungicide application to manage Phomopsis stem canker of sunflower (Helianthus annuus). American Society of Agronomy, Annual Meeting, San Antonio, TX. November 10-13.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2020
Citation:
Guidini, R., Braun, N., Markell, S., Harveson, R., and Mathew, F. 2020. Evaluation of fungicides for their efficacy against Phomopsis stem canker of sunflower. 42nd National Sunflower Association Annual Research Forum, Fargo, ND. January 7-8.
- Type:
Other
Status:
Accepted
Year Published:
2019
Citation:
Bush, C., Beck, R., and Mathew, F. 2019. An identification guide to common stem diseases of sunflower in South Dakota. SDSU Extension. Publication: P-00129.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
Guidini, R., Reinert, S., Hulke, B., Kane, N., Korah, M., Pogoda, C., Braun, N., Okello, P. N., Marek, L. F., and Mathew, F. M. 2019. Forty-one accessions have possible resistance to Diaporthe gulyae causing Phomopsis stem canker of sunflower (Helianthus annuus). American Phytopathological Society Annual Meeting, Cleveland, OH. August 3-7.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Mathew, F. M., Harveson, R. M., Johnson, M., Magarey, R. D., Isard, S. A., Braun, N., Gilley, M., Hansen, B., Halvorson, J., Carlson, C., Patrick, T., Rickey, A., and Markell, S. G. 2019. Growth stage vs. forecasting model based fungicide application to manage Phomopsis stem canker of sunflower (Helianthus annuus). American Phytopathological Society Annual Meeting, Cleveland, OH. August 3-7.
|
Progress 03/15/18 to 03/14/19
Outputs
Target Audience:Target audiences include researchers at universities and in the sunflower industry, sunflower farmers (including the board of directors of the National Sunflower Association and the South Dakota Oilseed Council), public and private agriculture professionals working on sunflowers, and the community-at-large. Efforts include extension and outreach, training industry personnel (e.g. Nuseed) and growers on the use of forecasting model to predict Phomopsis stem canker. Changes/Problems:As written in the proposal, one of the limitations of this project: 'The biggest challenge of this research will be occurrence of weather conditions that induce disease development in the multiple states. However, establishing trials in fields with a history of Phomopsis stem canker (MN, ND, and SD) and use of an irrigation system at a site with high Phomopsis levels from artificial inoculation (NE) will maximize disease establishment'. For 2018, we observed unexpected outcomes in our project - Overall, weather conditions did not favor development of Phomopsis stem canker at locations in North Dakota (Davenport and Carrington) despite the fact that spore traps were used to monitor the inocula of species of Phomopsis causing stem canker of sunflower. The state suffered a near absence of rainfall that is critical for disease development. In Nebraska and South Dakota, the disease did not develop until after flowering (R7 growth stage). Typically, the symptoms are observed at or before flowering (R5 growth stage). Based on the feedback from sunflower growers, they don't typically spray fungicides after R5 growth stage because there are no yield or economic benefits. Thus spraying fungicides based on the prediction model when the sunflower plants were past the R5 growth stage was not beneficial despite the presence of disease. Hence, for the third year (2019), the disease forecasting model will be validated at multiple locations across Nebraska, North Dakota and South Dakota in 2018. What opportunities for training and professional development has the project provided?In South Dakota, two undergraduate students (Mr. Mammen Korah and Ms. Janki Patel), a graduate student (M.S.) (Mr. Renan Guidini), and a post-doctoral research associate (Dr. Marina Johnson) who are partially funded by this grant, were trained in diagnosis of Phomopsis stem canker of sunflower. Research staff - Nathan Braun and Brian Kontz In North Dakota, a graduate student (M.S.) (Mr. Bryan Hansen) who is partially funded by this grant, was trained in diagnosis of Phomopsis stem canker of sunflower. Research staff - Michelle Gilley and Jessica Halvorson In Nebraska, an undergraduate student (Ms. Allison Rickey) who is partially funded by this grant, was trained in diagnosis of Phomopsis stem canker of sunflower. Research staff - Clay Carlson and Tyler Patrick How have the results been disseminated to communities of interest?Results have been shared through presentations at scientific conferences, extension outreach events, news releases, and interviews (as listed under "Products"). What do you plan to do during the next reporting period to accomplish the goals?Objective 1. To examine the weather variables and develop a Sunflower Phomopsis Risk Map (SPRM) to predict the development of Phomopsis stem canker of sunflower. The disease forecasting model was refined in 2018, and this model will be used in 2019. Objective 2. To validate SPRM under field conditions and determine the timing of fungicide applications. The model will be validated at multiple locations across Nebraska, North Dakota and South Dakota in 2019. Objective 3. To deliver SPRM to sunflower farmers and other stakeholders through extension and education activities. Results will be presented to the National Sunflower Association and the South Dakota Oilseed Council in 2019.
Impacts
What was accomplished under these goals?
Objective 1: Examine the weather variables and develop SPRM to predict the development of Phomopsis stem canker of sunflower (50% Accomplished) To develop regression models, weather data (air temperature (degrees Celsius), relative humidity (%), rainfall (mm), wind speed (m/s), solar radiation (W/m2), and leaf wetness (0 or 1)) were converted to 14-day moving averages. The disease assessment data from field trials in Minnesota, North Dakota, and South Dakota in 2014, 2015, 2016 and 2017 was converted to binary variables and a model was developed using SAS PROC LOGISTIC (v. 9.4; SAS Institute, Cary, NC). All predictor variables were included in the initial analysis using stepwise, forward, backward, and score-selection methods. Models were evaluated for accuracy by performing a goodness-of-fit test in LACKFIT analysis in PROC LOGISTIC. The model with the highest accuracy was then validated with an independent data set which was not used to develop the logistic regression model. This independent data set consisted of 12 locations-years representing locations from South Dakota, North Dakota, and Minnesota. The best model was developed using nine location-years and is given by the equation , where temperature (TMP), number of hours with relative humidity over 70% (RLH70), wind speed (WSP), and solar radiation (SRS) are the weather variables. Nine location-year datasets with daily observations were used to validate the selected model. These datasets were not previously used to develop the model. The model possessed excellent discrimination, with 0.66 max-rescaled R2 values and high predicted model accuracy of 78%. Based on a probability value at which sensitivity and specificity converged, a disease probability threshold of 0.40 was used to determine model success or failure. For each validation site, as well as total, the probability of disease occurrence was calculated by back-transforming from . The model predicted high (0.40 to 1), moderate (0.20 to 0.39) and low (0.01 to 0.19) risk of Phomopsis stem canker occurring at growth stage R1. When the forecasting model was validated, the model correctly predicted the severity of Phomopsis stem canker in 100% of the cases (sensitivity) and no disease in 92% of the cases (specificity). The risk map was uploaded onto iPIPE. Impact -The model was able to explain Phomopsis stem canker severity observed at R1 to R3 stage and at physiological maturity. Objective 2: Validate SPRM under field conditions and determine the timing of fungicide applications. (30% Accomplished) Fungicide trials were established at five locations in three states (Nebraska, North Dakota, and South Dakota) in 2018. In North Dakota the trials were established at the NDSU Research Farm (Carrington, ND) and with BASF (Davenport, ND). In South Dakota the trials were established at the SDSU Research Farms in Brookings and Volga. The trial in Volga was abandoned because of cutworm pressure. In North Dakota and South Dakota, the disease was evaluated under natural disease pressure. In Nebraska, the trial was established at the Scottsbluff Research Extension Center and the disease was introduced through Phomopsis-infested sunflower stalks that were spread between rows. The study was a randomized complete block design with a split-plot arrangement of 11 total treatments. Two sunflower varieties were set at the whole plot level: susceptible (CHS = RH400CL, Mycogen = N4HM354) and moderately resistant (CHS = Experimental line, Mycogen = Camaro II). A labeled sunflower fungicide (Headline, BASF, Research Triangle, NC) was used at eight growth stages, at the subplot level: non-treated control, V8 (late vegetative), R1 (bud initiation), R5 (flowering), V8+ R1, V8+ R5, R1+ R5, and V8 + R1 + R5. The remaining three treatments (one application of fungicide, two applications of fungicide and three applications of fungicide) were used to validate empirical model using the iPIPE risk map. We determined that besides weather variables, there are other factors that affect development of Phomopsis stem canker in sunflower. These factors include number of years since previous sunflower crop, number of Phomopsis-infected plants in previous sunflower crop, if sunflower is planted under irrigated conditions, and if Phomopsis stem canker was observed in the last five years. These were categorized as risk factors. Depending on these risk factors and whether the model predicted a disease probability > 0.40, fungicide applications were made at four locations. At the end of the season, disease severity was evaluated at growth stage R6-R8 (after flowering) using a 0-4 scale, where 0 = no infection, 1 = stem lesion < 2 inches, 2 = stem lesion > 2 inches, 3 = girdling stem lesion, and 4 = lodged plant. The rating scale was converted into disease severity index, which was calculated using the formula DSI (%) = ∑ {[(P x Q) / (M x N)] x 100} where P = disease severity rating, Q = number of infected plants having the same disease severity rating, M = total number of plants, N = maximum number on the disease severity rating scale. The disease severity index (DSI) and yield (obtained at the end of the season) will be analyzed using AGRICOLAE package and LSD analyses in R (v2.11.1; https://www.rstudio.com/). Results for Year 2 Nebraska: At Scottsbluff the environmental conditions were favorable for development of Phomopsis stem canker, however significant differences in yield (P > 0.05) were not observed among susceptible or resistant hybrids when sprayed with fungicide treatments. South Dakota: At Brookings the environmental conditions were favorable for development of Phomopsis stem canker, however, significant differences in yield or disease severity index rated at R5-R6 growth stage (P > 0.05) was not observed between hybrids subjected to fungicide treatments. Impact -Despite that significant differences in yield were not observed among fungicide treatments in Nebraska and South Dakota, greater yield was observed for susceptible sunflower hybrid when fungicides were sprayed based on the model prediction when compared to plants not sprayed with fungicides at all. Objective 3: Deliver SPRM to sunflower farmers and other stakeholders through extension and education activities. (40% Accomplished) Results have been shared through presentations at the Board of Directors meeting of the National Sunflower Association and the South Dakota Oilseed Council as well as at the growers meeting organized by Nuseed. Impact -Growers in Minnesota, Nebraska, North Dakota and South Dakota were educated on how a disease forecasting model works and can be used to spray fungicides.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2019
Citation:
Mathew, F. 2019. Update on Phomopsis stem canker of sunflower. National Sunflower Association Board Meeting. Fargo, ND. February 20.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Mathew, F. 2018. Sunflower 2.0. Nuseed Training Meeting. Pierre, SD. December 13.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Mathew, F. 2018. Phomopsis on sunflower = Management. AgHorizons, Pierre, SD. November 27-28.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Mathew, F. 2018. Phomopsis on sunflower = update. South Dakota Oilseed Council Board Meeting. Pierre, SD. November 26.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Mathew, F. 2018. Phomopsis. South Dakota Oilseed Council Board Meeting. Pierre, SD. April 5.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Mathew, F., Braun, N., Harveson, R., Carlson, C., Patrick, T., Rickey, A., Hansen, B., Gilley, M., Carruth, D., Cottrill, D., Fitterer, S., Nehring, J., Sindhu, A., Schaefer, J., and Markell, S. 2019. Phomopsis & fungicides. Proceedings of the 41st Annual Sunflower Research Forum, Fargo, ND. January 9-10.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Hansen, B., Gilley, M., Berghuis, B., Halvorson, J., Schatz, B., Mathew, F., Fitterer, S., Carruth, D., and Markell, S. 2019. The importance and management of Phoma black stem in sunflowers. Proceedings of the 41st Annual Sunflower Research Forum, Fargo, ND. January 9-10.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Mathew, F., Harveson, R., Gulya, T., Thompson, S., Block, C., and Markell, S. 2018. Phomopsis stem canker of sunflower. Plant Health Instructor. DOI: 10.1094/PHI-I-2018-1103-01.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Mathew, F., Harveson, R., Magarey, R., Isard, S., Ghimire, K., Gilley, M., Neilsen, K., Braun, N., Johnson, M., and Markell. S. 2018. Development of a prediction model to improve disease management in sunflower (Helianthus annuus). Proceedings of the 9th International Integrated Pest Management Symposium. Baltimore, MD. March 19-22.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Ghimire, K.., Kontz, B., Markell, S., and Mathew, F. 2018. Weeds as source of inoculum of Diaporthe gulyae, the causal agent of Phomopsis stem canker of sunflower. Proceedings of the 9th International Integrated Pest Management Symposium. Baltimore, MD. March 19-22.
|
Progress 03/15/17 to 03/14/18
Outputs
Target Audience:Scientific researchers at universities and in the sunflower industry, sunflower farmers (including the board of directors of the National Sunflower Association and the South Dakota Oilseed Council), agriculture professionals working on sunflowers, and the community-at-large. Changes/Problems:As written in the proposal, one of the limitations of this project: 'The biggest challenge of this research will be occurrence of weather conditions that induce disease development in the multiple states. However, establishing trials in fields with a history of Phomopsis stem canker (MN, ND, and SD) and use of an irrigation system at a site with high Phomopsis levels from artificial inoculation (NE) will maximize disease establishment'. For 2017, overall, weather conditions (rainfall, temperature of 22-25oC, relative humidity > 90%) did not favor development of Phomopsis stem canker at locations in North Dakota (Davenport and Carrington), where the state suffered a near absence of rainfall that is critical for disease development. Additionally, at Carrington, North Dakota, the trial was affected by bird damage (which was an unforeseen circumstance) and was not harvested. Hence, for the second year (2018), the disease forecasting model is being modified to accommodate the results from the 2017 field trials conducted in Nebraska and South Dakota. The model will be validated at multiple locations across Nebraska, North Dakota and South Dakota in 2018. What opportunities for training and professional development has the project provided?In South Dakota, two undergraduate students (Anjana Adhikari, SDSU and Jeffrey Lehman, South Dakota School of Mines and Technology), a graduate student (Krishna Ghimire, Ph.D. candidate in Agronomy, Horticulture, and Plant Science), and a PhDresearch associate (Dr. Marina Johnson) who are partially funded by this grant, were trained into diagnosis of Phomopsis stem canker of sunflower. The graduate student (Krishna Ghimire, Ph.D. candidate in Agronomy, Horticulture and Plant Science) has successfully finished two semesters of his doctoral program (Start date - Spring 2017). How have the results been disseminated to communities of interest?Results have been shared through presentations at scientific conferences, extension outreach events, news releases, and interviews. What do you plan to do during the next reporting period to accomplish the goals?Goal 1. The disease forecasting model is being modified to accommodate the results from the 2017 field trials conducted in Nebraska and South Dakota. Goal 2. The model will be validated at multiple locations across Nebraska, North Dakota and South Dakota in 2018. Goal 3. Results will be presented to the Board of Directors of the National Sunflower Association and the South Dakota Oilseed Council
Impacts
What was accomplished under these goals?
To develop regression models, correlation coefficients were calculated between disease index (Y) and weather variables (X). Weather variables were calculated based on the moving averages for the first 30, 45, 60, 90 days after planting sunflower and the last 3, 5, 10, and 14 days before the disease was assessed in field trials conducted in Nebraska, North Dakota and South Dakota in 2014, 2015 and 2016. Regression models were developed and validated by correlating observed disease severity with disease severity predicted from the disease forecasting model. Among the regression models, a 45 day post planting prediction model was selected based on its higher prediction accuracy, and a risk map was created using this model. The regression equationwas developed to predict Phomopsis stem canker is: Y= -57.79 +.2XSR +1.34XRH70 + 1.82XPdys, where Y = disease severity index (%); SR = Solar Radiation, calculated as the 45-day average (for solar radiation in W/m2; RH70 = Relative Humidity, calculated as the 45 day sum of the number of days with at least one hour of relative humidity > 70%; and Pdys = Precipitation Days, calculated as the 45 day sum of number of days with measurable precipitation. The risk map was uploaded onto iPIPE. The model is currently being modified to include 2017 disease data from South Dakota and Nebraska. The new model will be validated at multiple locations across Nebraska, North Dakota and South Dakota in 2018. Trials to validate the SPRM and assess fungicide application timing were established at a total of 6 locations in Nebraska, North Dakota and South Dakota in 2017. The study design was a randomized complete block with 10 total treatments consisting of a labeled sunflower fungicide (Headline, provided by BASF, Research Triangle, NC). Eight treatments (non-treated control, V8 (late vegetative), R1 (bud initiation), R5 (flowering), V8+ R1, V8+ R5, R1+ R5, and V8 + R1 + R5) were used on two types of hybrids: susceptible check and moderately resistant hybrid (provided by CHS and Mycogen). The remaining two treatments (one application of fungicide and two applications of fungicide) were used to validate the empirical model using the iPIPE risk map. In Nebraska, the trial was established at the Scottsbluff Research Extension Center and the disease was introduced into the trial through Phomopsis-infested sunflower stalks that were spread between rows. Conditions were made favorable for disease development through irrigation. Field details for the trial included: planting date (5/24/17); crop hybrid (susceptible hybrid -RH400CL; partially resistant hybrid - experimental line from CHS); application equipment (22-inch backpack sprayer, 20 psi, 66-inch-wide 7 feet height, 3.1 mph, water hardness 23.2, pump sprayer Nozzle 8002Vp Solstr); and first application date (3/31/17). In North Dakota, trials were established at the NDSU Research Farm (Carrington, ND) and at the BASF facility (Davenport, ND). All sites had a previous history of Phomopsis stem canker,therefore it was not necessary re-inoculate. Field details for the trial included: planting date (5/18/17 for Davenport and 6/1/17 for Carrington); crop hybrid (susceptible hybrid - Myc 8N421CLDM; partially resistant hybrid - Myc 8H449CLDM); application equipment (boom, 3 nozzles. 40 PSI @ 20 GPA); and first application date (7/5/17 for Carrington and 6/18/17 for Davenport). In South Dakota, the trials were established with farmer cooperators at Onida (Mr. Vance Huse) and Highmore (Mr. Dillon Baloun), as well as at the SDSU Research Farm (Felt Farm) at Brookings. All sites had a previous history of Phomopsis stem canker, so re-inoculation was not necessary. Field details for the trial included: planting date (6/8/10 for Highmore, 6/16/17 for Onida, and 5/29/17 for Felt Farm); crop hybrid (susceptible hybrid - RH400CL; partially resistant hybrid - experimental line from CHS); application equipment (boom, 4 nozzles, 2 per row. 35 PSI @ 15 GPA); and first application date (7/18/17 for Highmore and Onida and 7/14/17 for Felt Farm). Depending on the risk factors and prediction from the iPIPE map, fungicide applications were made at five out of six locations. Since the Davenport, ND site did not have any risk factors, no fungicide applications were made as per as the prediction model. At the end of the season, disease severity was evaluated at growth stage R5 to R7 (after flowering) using a 0-4 scale, where 0 = no infection, 1 = stem lesion < 2 inches, 2 = stem lesion > 2 inches, 3 = girdling stem lesion, and 4 = lodged plant. The rating scale was converted into a disease severity index, which was calculated using the formula DSI (%) = ∑ {[(P x Q) / (M x N)] x 100}, where P = disease severity rating, Q = number of infected plants having the same disease severity rating, M = total number of plants, N = maximum number on the disease severity rating scale (Galanihe et al. 2004). The disease severity index (DSI) and yield (obtained at the end of the season) were analyzed to identify if the fungicide applications were effective when compared to non-treated check using AGRICOLAE package in R (v2.11.1; https://www.rstudio.com/). We determined that besides weather variables, there are factors that affect development of Phomopsis stem canker of sunflower. These include: number of years since the previous sunflower crop, percentage of Phomopsis-infected plants in previous sunflower crop, if sunflower is planted under irrigated conditions, and if Phomopsis stem canker was observed in the last 5 years. These were categorized as risk factors, and were assigned risk points (in parentheses) which farmers would calculate and if the risk factors > 40 fungicides would be sprayed based on the prediction model: Number of years since previous sunflower crop (0 for >6 years, 5 for 3-6 years, 10 for 1-2 years); Percentage of infected plants in previous sunflower crop (0 for 0%, 5 for 1-10%, 10 for 11-30%, 15 for 30-100%); Is irrigation used (0 for no, 5 for yes), and was Phomopsis observed in the last 5 years (0 for no, 5 for yes). These factors were not included in the regression equation developed in year 1, but we are assessing how they could be incorporated. For 2017, weather conditions (rainfall, temperature of 22-25oC, relative humidity > 90%) did not favor development of Phomopsis stem canker at locations in North Dakota. At Nebraska (Scottsbluff) and South Dakota (Brookings, Highmore and Onida) sites we observed Phomopsis stem canker development late in the trials when weather conditions became favorable. Disease severity was assessed at these locations. Results from first-year trials established in Scottsbluff, NE and Onida, SD indicate that using a partially resistant hybrid in combination with fungicide (application based on the disease forecasting model) can improve yield. Nebraska: For the susceptible hybrid, significant differences in disease severity index rated at R7 growth stage (P < 0.05) were observed among the fungicide treatments; treatment # 11 wherein Headline was sprayed based on the prediction model had the lowest disease severity index. For the partially resistant hybrid, significant differences in yield (P < 0.05) were observed among the fungicide treatments; treatment # 11 wherein Headline was sprayed based on the prediction model had the highest yield. South Dakota: At Brookings and Highmore, significant differences in yield or disease severity index at R5-R6 growth stage (P > 0.05) were not observed among the fungicide treatments for susceptible or partially resistant hybrids. At Onida, on the susceptible hybrid, significant differences in yield (P < 0.05) were observed from application of fungicides to manage Phomopsis stem canker; wherein Headline sprayed based on the prediction model had the highest yield. Preliminary results were presented to the Board of Directors of the National Sunflower Association and the South Dakota Oilseed Council
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2018
Citation:
Mathew, F., Harveson, R., Johnson, M., Kontz, B., Gilley, M., Ghimire, K.*, Braun, N., Nielsen, K., Magarey, R., Isard, S., and Markell, S. 2018. Predicting Phomopsis stem canker. Proceedings of the 40th Annual Sunflower Research Forum, Fargo, ND. January 10-11, 2018 (Talk).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2018
Citation:
Gilley, M., Halvorson, J., Berghuis, B.*, Hansen, B., Fitterer, S., Carruth, D., Mathew, F., and Markell, S. 2018. Management of Phoma with Fungicide. Proceedings of the 40th Annual Sunflower Research Forum, Fargo, ND. January 10-11, 2018 (Talk).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2018
Citation:
Ghimire, K.*, Kontz, B., Markell, S., and Mathew F. 2018. Identification of Phomopsis gulyae on weed host. Proceedings of the 40th Annual Sunflower Research Forum, Fargo, ND. January 10-11, 2018 (Poster).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2018
Citation:
Ghimire, K.*, Markell, S. Harveson, B., Gilley, M., Neilson, K., Braun, N., and Mathew, F. 2018. Quantifying airborne inoculum of Phomopsis. Proceedings of the 40th Annual Sunflower Research Forum, Fargo, ND. January 10-11, 2018 (Talk).
- Type:
Other
Status:
Other
Year Published:
2017
Citation:
Mathew, F. 2017. Phomopsis. South Dakota Oilseed Council Board of Directors Meeting, Pierre, SD. December 6, 2017 (Talk).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2017
Citation:
Mathew, F. 2017. Phomopsis and sunflower. Ag Horizons Conference, Pierre, SD. December 5 and 6, 2017 (Talk).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2017
Citation:
Mathew, F., Harveson, R., Magarey, R., Isard, S., Ghimire, K.*, Gilley, M., Nielsen, K., Braun, N., and Markell, S. 2017. Improving disease management in sunflower (Helianthus annuus). USDA-NIFA PROJECT DIRECTORS MEETING, Washington D.C. October 30-31, 2017 (Poster).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2017
Citation:
Kontz, B., Adhikari, A., Olson, T., Johnson, P., Markell, S., and Mathew, F. 2017. Cross pathogenicity of Diaporthe gulyae on sunflower and weed hosts. American Phytopathological Society Annual Meeting, San Antonio, TX. August 5-August 9, 2017 (Poster).
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