Updated July 28, 2021:
Program I. Extension/Outreach and Farmer Feedback

1.1 Extension coordination and deliverables
Participants: Kelley Tilmon* (Ohio State University), with contributions all team members *Project leader

Extension deliverables described in the previous progress report were unable to be completed because of rebudgeting following budget cuts to Year 3 funding. Work on electronic versions will resume after the 2021 field season and distributed through online channels.

1.2 Determining farmer needs and priorities
Participants: Tom Hunt* (University of Nebraska), Kevin Rice* (University of Missouri) *Project leaders

This objective is focused on farmer participation and feedback to assess needs and thoughts. We contracted with a professional focus group consultant, Dr. Mary Anne Casey, to help us conduct a series of farmer focus groups. Focus group sessions were conducted with 4-5 participants representing four quadrants of the North Central Region (NE, NW, SW. SE) and a global session comprised of 5 crop consultants/advisors. This project was completed on schedule and two reports were written documenting and summarizing farmer priorities for soybean pest management research and communication – a shorter executive summary report, and a longer full report. These reports have been provided to NCSRP for distribution to various soybean checkoff organizations and are appended to this document. This report helped inform our current proposal to the NCSRP and it is our hope that the results of this report will also help guide future research and outreach efforts.

Program II. Insect Management and Profitability

2.1 Management guidelines for defoliating insects
Participants: Nick Seiter* (University of Illinois), Erin Hodgson (Iowa State), Brian McCornack (Kansas State), Chris DiFonzo (Michigan State), Christian Krupke (Purdue), Kelley Tilmon (Ohio State). *Project leader

Sampling of commercial soybean fields in 7 states reveals that insect defoliation rarely causes economic damage to soybean. Out of 65 commercial soybean fields sampled in 2019 and 2020, only 1 was above established economic thresholds for insect defoliation. All but 6 fields were below 5% defoliation.During sampling, we collected over 600 images of soybean canopy defoliation, which will be used to develop and improve visual sampling aids (including field guides, a fact sheet, and a web-based scout-training quiz). During summer 2021, we are collecting additional images of soybean defoliation and the responsible insects for use in print and digital extension materials. In addition, we are producing a series of short instructional videos and an interactive web-based training module. A manuscript is in preparation based on the results of our field sampling. An additional extension manuscript will present recommendations for managing defoliating insects in the North Central U.S. and economic thresholds for soybean defoliation based on published research.

2.2 Cover crops: pest and beneficial insects in cereal rye to soybean transition systems
Participants: Justin McMechan* (University of Nebraska), Shawn Conley (University of Wisconsin), Louis Hesler and Shannon Osborne (USDA ARS South Dakota), Thomas Hunt (University of Nebraska), Bruce Potter (University of Minnesota), Kevin Rice (University of Missouri), Nick Seiter (University of Illinois); Kelley Tilmon (Ohio State University), and Robert Wright (University of Nebraska). *Project leader

For 2021, cover crops have been terminated, soybean planted, and data collected on arthropods through pitfalls traps and injury to soybean. No significant injury to soybean as a result of a rye cover crop was reported from any of the 10 sites this year. With this year’s data collection, a total of 31 site years of data has been collected which will be analyzed and summarized this fall. Identification of arthropods collected from pitfall traps is currently in progress. Wet weather caused delays in soybean planting this year resulting in excessive cereal rye cover crop growth at some sites.


2.3 Pollinators to improve soybean yield
Participants: Reed Johnson*, Chia Lin, and Kelley Tilmon (Ohio State University) *Project leader

We received permission from soybean growers to evaluate the effects of honey bee pollination on soybean yield in nine fields adjacent to honey bee apiaries. When seed pods are mature and before each field is harvested, we will sample plants along a transect at 100 m intervals to evaluate yield and pod development in relation to the distance from the apiaries. Seeds from the fields where yield is being evaluated are also planted in small plots (10 ft wide by 20 ft long) in a common garden design at the Waterman Agricultural and Natural Resources Laboratory in Columbus, OH. We will evaluate floral traits and measure nectar productivities in these varieties. In addition to the common garden study, we have planted 16 soybean varieties, some identified as high-yield, nectar-rich varieties from the 2019 – 2020 surveys, in 12 caged plots at Waterman. Fine mesh covers will be installed to exclude wild pollinators during soybean bloom. Small honey bee colonies will be installed in six of these cages. Yield and pod development will be compared between plants with and without honey bee pollination for each variety.

2.4 Insecticide-resistant soybean aphids
Participants: Robert Koch* (University of Minnesota), Ana Vélez (University of Nebraska), Janet Knodel (North Dakota State University); with contributions from other NCSRP participants including Andy Michel (Ohio State University), Erin Hodgson (Iowa State University), Adam Varenhorst (South Dakota State University), Louis Hesler (USDA ARS South Dakota), and Tom Hunt (University of Nebraska) *Project leader

Five soybean aphid populations were collected in 2020 and maintained in a greenhouse. These included four insecticide-resistant populations from Minnesota and one susceptible population from North Dakota. Data were analyzed from experiments in growth chambers and the greenhouse to assess potential fitness costs of pyrethroid resistance in soybean aphid. Preliminary results suggest that pyrethroid resistance in soybean aphid is not associated with a measurable decrease in aphid fitness (size, reproduction, survival, etc.). Data comparing the efficacy of field applications of pyrethroids to the levels of mortality observed in glass-vial assays were limited due to lack of aphid infestations in collaborating states. The field applications in controlled and replicated experiments, confirmed the continued presence of insecticide resistant aphids.

2.5 Soybean stem borer
Participants: Kevin Rice* (University of Missouri), Robert Wright (University of Nebraska), Raul Villanueva (University of Kentucky) *Project leader

Large-scale field experiments were set up in soybean fields to test the efficacy of sunflower as a trap crop for dectes stem borer. Visual and weekly sweep samples were collected starting in June and will continue throughout August. Prior to harvest, we will assess stem borer damage in soybean and control treatments. Additional assessments of cocklebur weevil infestations in sunflower trap crops are being quantified.

Program III. Aphid Resistant Varieties and Aphid Virulence Management
3.1 Advancing aphid resistant soybeans through a public-private partnership
Participants: Matt O’Neal* (Iowa State University), Andy Michel* (Ohio State University), Mauricio Urrutia* (Corteva), David Onstad* (Corteva), Kelley Tilmon (Ohio State University), Thomas Hunt (University of Nebraska), Deirdre Prischmann (North Dakota State University), Adam Varenhorst (South Dakota State University), Louis Hesler (USDA ARS South Dakota). *Project leaders

During the winter of 2020 and spring of 2021, Dr. O’Neal and Ivair Valmorbida (PhD candidate) gathered the yield and aphid data from the collaborators. Delays occurred due to the pandemic. We are preparing a finally summary of these data, and preparing a factsheet for the 2022 growing season on the benefits of aphid-resistant soybeans. We continue to collaborate with our colleagues at Corteva on aphid management and biology. One example of this collaboration is that Corteva’s entomologists are sharing rearing space during the pandemic such that there are back-up colonies in case our university rearing space became inaccessible.

With regard to field testing aphid resistant soybean varieties for commercialization: We have maintained multiple colonies of aphids that vary in their ability to survive on aphid-resistant soybeans. These lines are shared with other PIs and with and agribusinesses in need of aphids to screen varieties for resistance. This work includes a collaboration with Dr. Danny Singh (Plant Breeder, ISU) who is evaluating soybean germplasm and advanced cultivars for commercial release. This screening occurred during the winter of 2020 and will continue in winter 2021. In addition we have completed the following: We have completed bioassays for aphids collected in 2020. The frequency of any virulence was low (> 2%) in any individual population. Through our screening, we have found 3 aphid colonies that appear to survive on the Rag1/2/3 triple stack. Continued bioassays with these colonies are ongoing with seed from Brian Diers.
With regard to insect resistance management (IRM) for aphid-resistant soybeans: From January to July of 2021, Dr. David Onstad of Corteva has meet with Drs. O’Neal and Michel to develop a model to explore how aphids may respond to the wide-spread commercial release aphid-resistant soybeans. Dr. Onstad has developed a basic model and is gathering data to inform it, regarding the fitness cost associated with virulence to aphid-resistance. We have also added additional data and input from a colleague not initially involved in this project, Dr. Adam Varenhorst of South Dakota State University. Delays in developing the model occurred through adding Dr. Varenhorst to the NDAs required for this public private partnership.

Dr. O’Neal has collaborated with a new faculty member, Dr. Rana Parshad, and his PhD student Aniket Banerjee, to develop a model to explore how virulent and avirulent aphids interact on aphid-resistant soybeans. This was submitted in July to the Journal of Economic Entomology (Banerjee et al. In review). This manuscript includes data that is being used by Dr. Onstad for our larger IRM model. In anticipation of future field work to explore if the frequency of virulent aphids increases with increasing use of aphid-resistant soybeans, Dr. Michel is validating genetic markers. These markers will be used in field work in the 2022 season.

3.2 Soybean breeding for aphid resistance
Participants: Brian Diers* (University of Illinois), Glen Hartman* and Doris Lago-Kutz (USDA-ARS) *Project leaders

Registration of 64 soybean germplasm lines with all combinations of five soybean aphid resistance genes in two genetic backgrounds, and agronomic and phenotyping (against four known soybean aphid biotypes) is in progress.

Program IV. Insect Monitoring
4.1 Biological control of soybean aphid
Participants: George Heimpel*, with contributions from other project team members *Project leader

We have started collecting data and field samples for 2021, with all colleagues reporting their early season numbers. More data will be coming as the season progresses. We found soybean aphids and black mummies early in the season in Saint Paul and Rosemount, MN, including one Aphelinus certus female on June 16th, 2021, when densities were 2 aphids per V3 soybean plant in Minnesota. Michigan also reported soybean aphids and mummies at this time, with 10.4 aphids per plant and 6 A. certus from one field, and from another field 18 A. certus and 2 Lysiphlebus testaceipes. Iowa reported a few plants with high aphid numbers, along with one black and 3 tan mummies. Since this early flush of aphids all sites report low densities, below 0.5 aphids per plant in weekly sampling in Minnesota. Soybean aphid densities were generally low across the region throughout the 2020 field season, except for the 3 states of Iowa, Minnesota, and Wisconsin which had low densities in the early season, moderate in the mid season, and high numbers in late August with levels above the spraying threshold (250 aphids per plant) in Iowa and Minnesota. Aphelinus numbers were low in 2020, with most states reporting no mummies. In August A. certus were at moderate densities of 0.5 to 4.4 per plant in Minnesota, Wisconsin, and Iowa. These numbers represent limited sampling of 1 to 4 fields in June, July, and August, and A. certus was not found until late July. Hyperparasitism was undetected in most sites in 2020. From Wisconsin July 28th, we received 50 black mummies from which emerged 5 Alloxysta sp. individuals (Figitidae). In 2020 hyperparasitism by Alloxysta brevis ranged between 1% for a statewide Minnesota survey, conducted over 6 weeks, and 10% hyperparasitism in Wisconsin in late July. While hyperparasitism remains a minor concern, the numbers are not increasing; in 2017 we reported 26% hyperparasitism regionally. In 2017 we found only 7 of 45 hyperparasitoids were Alloxysta, while other years Alloxysta has been the most abundant. Alloxysta is of special interest as we have shown the most abundant of the 3 Alloxysta species in the region, A. brevis, to be thelytokous.

4.2 Monitoring soybean aphids and other soybean insect pests in suction traps
Participants: Glen Hartman* and Doris Lagos-Kutz (USDA-ARS/ University of Illinois) and Nick Seiter (University of Illinois), with contributions from other project team members *Project leader

34 suction insect monitoring suction traps began operation on May 14, 2021, located in Illinois (5 traps), Indiana (5), Iowa (4), Kansas (1), Louisiana (1), Michigan (5), Minnesota (4), Missouri (1), Nebraska (2) and Wisconsin (6). The samples have been collected weekly and shipped to Doris Lagos-Kutz. All the samples have been processed (cleaned and stored in 95% ethanol at -20 Celsius) and sorted up to July 9th, 2021. Aphid data has been stored in excel files and website https://www.eddmaps.org, and shared with our collaborators and extension personnel through https://suctiontrapnetwork.org/data/. Data from other crop pests and predators have been stored in excel files. We are working on making these additional data publicly available through eddmaps.

View uploaded report

View uploaded report 2

Program I. Extension/Outreach and Farmer Feedback

Determining farmer needs and priorities
Participants: Tom Hunt* (University of Nebraska), Kevin Rice* (University of Missouri) *Project leaders
This objective is focused on farmer participation and feedback to assess needs and thoughts. We contracted with a professional focus group consultant, Dr. Mary Anne Casey, to help us conduct a series of farmer focus groups. Focus group sessions were conducted with 4-5 participants representing four quadrants of the North Central Region (NE, NW, SW. SE) and a global session comprised of 5 crop consultants/advisors. This project was completed on schedule and two reports were written documenting and summarizing farmer priorities for soybean pest management research and communication – a shorter executive summary report, and a longer full report. These reports have been provided to NCSRP for distribution to various soybean checkoff organizations and are appended to this document. This report helped inform our current proposal to the NCSRP and it is our hope that the results of this report will also help guide future research and outreach efforts.

Program II. Insect Management and Profitability
Management guidelines for defoliating insects
Participants: Nick Seiter* (University of Illinois), Erin Hodgson (Iowa State), Brian McCornack (Kansas State), Chris DiFonzo (Michigan State), Christian Krupke (Purdue), Kelley Tilmon (Ohio State). *Project leader
Sampling of commercial soybean fields in 7 states reveals that insect defoliation rarely causes economic damage to soybean. Out of 65 commercial soybean fields sampled in 2019 and 2020, only 1 was above established economic thresholds for insect defoliation. All but 6 fields were below 5% defoliation.During sampling, we collected over 600 images of soybean canopy defoliation, which will be used to develop and improve visual sampling aids (including field guides, a fact sheet, and a web-based scout-training quiz). During summer 2021, we are collecting additional images of soybean defoliation and the responsible insects for use in print and digital extension materials. In addition, we are producing a series of short instructional videos and an interactive web-based training module. A manuscript is in preparation based on the results of our field sampling. An additional extension manuscript will present recommendations for managing defoliating insects in the North Central U.S. and economic thresholds for soybean defoliation based on published research.

Cover crops: pest and beneficial insects in cereal rye to soybean transition systems
Participants: Justin McMechan* (University of Nebraska), Shawn Conley (University of Wisconsin), Louis Hesler and Shannon Osborne (USDA ARS South Dakota), Thomas Hunt (University of Nebraska), Bruce Potter (University of Minnesota), Kevin Rice (University of Missouri), Nick Seiter (University of Illinois); Kelley Tilmon (Ohio State University), and Robert Wright (University of Nebraska). *Project leader
For 2021, cover crops have been terminated, soybean planted, and data collected on arthropods through pitfalls traps and injury to soybean. No significant injury to soybean as a result of a rye cover crop was reported from any of the 10 sites this year. With this year’s data collection, a total of 31 site years of data has been collected which will be analyzed and summarized this fall. Identification of arthropods collected from pitfall traps is currently in progress. Wet weather caused delays in soybean planting this year resulting in excessive cereal rye cover crop growth at some sites.

Pollinators to improve soybean yield
Participants: Reed Johnson*, Chia Lin, and Kelley Tilmon (Ohio State University) *Project leader
We received permission from soybean growers to evaluate the effects of honey bee pollination on soybean yield in nine fields adjacent to honey bee apiaries. When seed pods are mature and before each field is harvested, we will sample plants along a transect at 100 m intervals to evaluate yield and pod development in relation to the distance from the apiaries. Seeds from the fields where yield is being evaluated are also planted in small plots (10 ft wide by 20 ft long) in a common garden design at the Waterman Agricultural and Natural Resources Laboratory in Columbus, OH. We will evaluate floral traits and measure nectar productivities in these varieties. In addition to the common garden study, we have planted 16 soybean varieties, some identified as high-yield, nectar-rich varieties from the 2019 – 2020 surveys, in 12 caged plots at Waterman. Fine mesh covers will be installed to exclude wild pollinators during soybean bloom. Small honey bee colonies will be installed in six of these cages. Yield and pod development will be compared between plants with and without honey bee pollination for each variety.

Insecticide-resistant soybean aphids
Participants: Robert Koch* (University of Minnesota), Ana Vélez (University of Nebraska), Janet Knodel (North Dakota State University); with contributions from other NCSRP participants including Andy Michel (Ohio State University), Erin Hodgson (Iowa State University), Adam Varenhorst (South Dakota State University), Louis Hesler (USDA ARS South Dakota), and Tom Hunt (University of Nebraska) *Project leader
Five soybean aphid populations were collected in 2020 and maintained in a greenhouse. These included four insecticide-resistant populations from Minnesota and one susceptible population from North Dakota. Data were analyzed from experiments in growth chambers and the greenhouse to assess potential fitness costs of pyrethroid resistance in soybean aphid. Preliminary results suggest that pyrethroid resistance in soybean aphid is not linked to any detrimental traits for the aphids, making it more likely for the insecticide resistance to spread. Data comparing the efficacy of field applications of pyrethroids to the levels of mortality observed in glass-vial assays were limited due to lack of aphid infestations in collaborating states. The field applications in controlled and replicated experiments, confirmed the continued presence of insecticide resistant aphids in the region.

Soybean stem borer
Participants: Kevin Rice* (University of Missouri), Robert Wright (University of Nebraska), Raul Villanueva (University of Kentucky) *Project leader
Large-scale field experiments were set up in soybean fields to test the effect of sunflower as a trap crop for dectes stem borer, to attract them away from soybean. Visual and weekly sweep samples were collected starting in June and will continue throughout August. Prior to harvest, we will assess stem borer damage in soybean and control treatments. Additional assessments of cocklebur weevil infestations in sunflower trap crops are being quantified. Results will be summarized in the fall.

Program III. Aphid Resistant Varieties and Aphid Virulence Management
Advancing aphid resistant soybeans through a public-private partnership
Participants: Matt O’Neal* (Iowa State University), Andy Michel* (Ohio State University), Mauricio Urrutia* (Corteva), David Onstad* (Corteva), Kelley Tilmon (Ohio State University), Thomas Hunt (University of Nebraska), Deirdre Prischmann (North Dakota State University), Adam Varenhorst (South Dakota State University), Louis Hesler (USDA ARS South Dakota). *Project leaders
During the winter of 2020 and spring of 2021, Dr. O’Neal and Ivair Valmorbida (PhD candidate) gathered yield and aphid data from the collaborators. Delays occurred due to the pandemic. We are preparing a final summary of these data, and preparing a factsheet for the 2022 growing season on the benefits of aphid-resistant soybeans. We continue to collaborate with our colleagues at Corteva on aphid management and biology. One example of this collaboration is that Corteva’s entomologists are sharing rearing space during the pandemic such that there are back-up colonies in case our university rearing space became inaccessible.
With regard to field testing aphid resistant soybean varieties for commercialization: We have maintained multiple colonies of aphids that vary in their ability to survive on aphid-resistant soybeans. These lines are shared with other researchers and with agribusinesses in need of aphids to screen varieties for resistance. This work includes a collaboration with Dr. Danny Singh (Plant Breeder, ISU) who is evaluating soybean germplasm and advanced cultivars for commercial release. This screening occurred during the winter of 2020 and will continue in winter 2021. In addition we have completed the following: We have completed bioassays for aphids collected in 2020. The frequency of any virulence was low (> 2%) in any individual population. Through our screening, we have found 3 aphid colonies that appear to survive on the Rag1/2/3 triple stack. Continued bioassays with these colonies are ongoing with seed from Brian Diers.
With regard to insect resistance management (IRM) for aphid-resistant soybeans: From January to July of 2021, Dr. David Onstad of Corteva has meet with Drs. O’Neal and Michel to develop a model to explore how aphids may respond to the wide-spread commercial release aphid-resistant soybeans. Dr. Onstad has developed a basic model and is gathering data to inform it, regarding the fitness cost associated with virulence to aphid-resistance. We have also added additional data and input from a colleague not initially involved in this project, Dr. Adam Varenhorst of South Dakota State University. Delays in developing the model occurred through adding Dr. Varenhorst to the NDAs required for this public private partnership.
Dr. O’Neal has collaborated with a new faculty member, Dr. Rana Parshad, and his PhD student Aniket Banerjee, to develop a model to explore how virulent and avirulent aphids interact on aphid-resistant soybeans. This was submitted in July to the Journal of Economic Entomology (Banerjee et al. In review). This manuscript includes data that is being used by Dr. Onstad for our larger IRM model. In anticipation of future field work to explore if the frequency of virulent aphids increases with increasing use of aphid-resistant soybeans, Dr. Michel is validating genetic markers. These markers will be used in field work in the 2022 season.

Soybean breeding for aphid resistance
Participants: Brian Diers* (University of Illinois), Glen Hartman* and Doris Lago-Kutz (USDA-ARS) *Project leaders
Registration of 64 soybean germplasm lines with all combinations of five soybean aphid resistance genes in two genetic backgrounds, and agronomic and phenotyping (against four known soybean aphid biotypes) is in progress.

Program IV. Insect Monitoring
Biological control of soybean aphid
Participants: George Heimpel*, with contributions from other project team members *Project leader
We have started collecting data and field samples for 2021, with all colleagues reporting their early season numbers. More data will be coming as the season progresses. We found soybean aphids and black mummies early in the season in Saint Paul and Rosemount, MN, including one Aphelinus certus female on June 16th, 2021, when densities were 2 aphids per V3 soybean plant in Minnesota. Michigan also reported soybean aphids and mummies at this time, with 10.4 aphids per plant and 6 A. certus from one field, and from another field 18 A. certus and 2 Lysiphlebus testaceipes. Iowa reported a few plants with high aphid numbers, along with one black and 3 tan mummies. Since this early flush of aphids all sites report low densities, below 0.5 aphids per plant in weekly sampling in Minnesota. Soybean aphid densities were generally low across the region throughout the 2020 field season, except for the 3 states of Iowa, Minnesota, and Wisconsin which had low densities in the early season, moderate in the mid season, and high numbers in late August with levels above the spraying threshold (250 aphids per plant) in Iowa and Minnesota. Aphelinus numbers were low in 2020, with most states reporting no mummies. In August A. certus were at moderate densities of 0.5 to 4.4 per plant in Minnesota, Wisconsin, and Iowa. These numbers represent limited sampling of 1 to 4 fields in June, July, and August, and A. certus was not found until late July. Hyperparasitism was undetected in most sites in 2020. From Wisconsin July 28th, we received 50 black mummies from which emerged 5 Alloxysta sp. individuals (Figitidae). In 2020 hyperparasitism by Alloxysta brevis ranged between 1% for a statewide Minnesota survey, conducted over 6 weeks, and 10% hyperparasitism in Wisconsin in late July. While hyperparasitism remains a minor concern, the numbers are not increasing; in 2017 we reported 26% hyperparasitism regionally. In 2017 we found only 7 of 45 hyperparasitoids were Alloxysta, while other years Alloxysta has been the most abundant. Alloxysta is of special interest as we have shown the most abundant of the 3 Alloxysta species in the region, A. brevis, to be thelytokous.

4.2 Monitoring soybean aphids and other soybean insect pests in suction traps
Participants: Glen Hartman* and Doris Lagos-Kutz (USDA-ARS/ University of Illinois) and Nick Seiter (University of Illinois), with contributions from other project team members *Project leader
34 suction insect monitoring suction traps began operation on May 14, 2021, located in Illinois (5 traps), Indiana (5), Iowa (4), Kansas (1), Louisiana (1), Michigan (5), Minnesota (4), Missouri (1), Nebraska (2) and Wisconsin (6). The samples have been collected weekly and shipped to Doris Lagos-Kutz. All the samples have been processed (cleaned and stored in 95% ethanol at -20 Celsius) and sorted up to July 9th, 2021. Aphid data has been stored in excel files and website https://www.eddmaps.org, and shared with our collaborators and extension personnel through https://suctiontrapnetwork.org/data/. Data from other crop pests and predators have been stored in excel files. We are working on making these additional data publicly available through eddmaps.