Project Details:

Title:
Soybean Entomology Research and Extension in the North Central Region

Parent Project: Soybean entomology in the North Central region: Management and outreach for new and existing pests
Checkoff Organization:North Central Soybean Research Program
Categories:Insects and pests, Nematodes
Organization Project Code:GRT00060847
Project Year:2021
Lead Principal Investigator:Kelley Tilmon (The Ohio State University)
Co-Principal Investigators:
Keywords: Insecticides, pheromones, soybean gall midge, soybean pests, Stink Bugs

Contributing Organizations

Funding Institutions

Information and Results

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Project Summary

The subject of this proposal is research and outreach on soybean entomology in the North Central Region. This is a Year 3 renewal proposal for a 3-year proposal submitted in FY19. Year 2 is currently underway, as we prepare for the second field season of the project (Summer 2020). Soybean insect pests not only reduce yield, but can also reduce grain quality, altering oil and protein content (Rupe and Luttrell 2008). Thus insect pests can affect soybean value by affecting both yield and composition. In addition, inefficient pest management adds to the expense of farm production, cutting into farmers’ bottom lines. This proposal involves collaborative research among 25 researchers in 13 states, working on four main program areas encompassing I. Extension/outreach and farmer feedback, II. Insect management and profitability, III. Aphid resistant varieties and virulence management, and IV. Insect monitoring. The objectives within these programs address the efficient, cost-effective management of defoliating (chewing) insects; the role of cover crops relative to insects in soybean production; aphid resistance to insecticides (a documented and growing problem in the region); management of soybean stem borer (Dectes); the ability of honey bees to improve soybean yield; a public-private partnership with Corteva (formerly Pioneer Hi-Bred International) to advance aphid resistant soybean varieties for wide scale commercialization; regional monitoring programs for pest and beneficial insects; and a survey program to assess farmer priorities and needs to inform future research and extension. In addition, we have an extension objective with a dedicated budget line to produce deliverables and disseminate project results.

This project builds on past NCSRP research and investment in several important ways. Previous work on the potential for insecticide resistance in aphids and tools to measure this resistance are now being used because insecticide-resistant soybean aphids have been found in four states, with the problem spreading each year. NCSRP research to develop aphid resistant soybean lines is nearing fruition as a major seed distributor (Corteva/Pioneer) is moving towards commercialization; the collaborative work with industry described in the current proposal will advance this effort. NCSRP research on pollinators in soybean has advanced to the point where we are ready to assess the yield improvement that honey bees may provide in soybean production. This proposal also has objectives looking at the role of cover crops in pest management; the spreading problem of soybean stem borer; and maximizing the efficiency of scouting and management of defoliating insects (such as Japanese beetle, clover worm, bean leaf beetle).


Project Objectives

Program I. Extension/Outreach and Farmer Feedback

1.1 Extension coordination and deliverables
1.2 Determining farmer needs and priorities

Program II. Insect Management and Profitability
2.1 Management guidelines for defoliating insects
2.2 Cover crops: pest and beneficial insects in cereal rye to soybean transition systems
2.3 Pollinators to improve soybean yield
2.4 Insecticide-resistant soybean aphids
2.5 Soybean stem borer

Program III. Aphid Resistant Varieties and Aphid Virulence Management
3.1 Advancing aphid resistant soybeans through a public-private partnership
3.2 Soybean breeding for aphid resistance

Program IV. Insect Monitoring
4.1 Biological control of soybean aphid
4.2 Monitoring soybean aphids and other soybean insect pests in suction traps

Project Deliverables

See file upload below

Progress of Work

Updated April 20, 2021:
1.1 Extension coordination and deliverables
Participants: Kelley Tilmon* (Ohio State University), with contributions all team members *Project leader
During the reporting period we began work on an updated Second Edition of the popular Stink Bugs of the North Central Region field guide. Because of budget cutbacks and rebudgeting demands we will not be able to immediately supply these deliverables in hard copy, but we will create electronic versions for free online distribution. We will be design them so that they can readily be turned into print versions when resources permit. We have also nearly completed layout on an extension factsheet on pollinators found in soybean in the region. Some funds were already set aside for this publication before budget cuts and it is a less expensive item to produce so some hard copies will be available. In addition, the NC Region project teamed up with the Gall Midge project to combine resources to produce a Soybean Gall Midge Alert Card, a postcard-sized quick ID and alert communication designed for easy distribution, especially in areas where gall midge has not yet arrived. We collaborated with several state soybean boards to arrange for a distribution of distribution of 74,000 copies in 14 states, in addition to online delivery.

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. Dr. Casey conducted the NCSRP focus group sessions on Feb 23, March 9, 10, 23, 25, 2021. Drs. Tom Hunt and Kevin Rice facilitated. Interview responses are being analyzed with the final report expected in early May 2021. This report will be distributed to various soybean checkoff organizations. The results of this report will help inform our future research and extension efforts and also our next proposal to the NCSRP.

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
In 2020, we sampled 33 fields in 6 states using a reduced protocol (10 sample points per field) to measure the extent of defoliation. Current efforts are focused on data analysis and preliminary manuscript preparation. Efforts in 2021 will focus on developing Extension materials based on this work.

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
Yield data analysis from 2020 found that with the exception of two sites there was no significant reductions in yield with delayed termination of a rye cover crop. In general, arthropod data from 2020 showed an increase in total arthropod activity with delayed terminations compared to early or no cover crop. The source of increase arthropod activity in pitfall traps with delayed terminations varied between sites but was primarily associated with ground beetles, spiders, or sap beetles. No significant pest pressure was associated with a rye cover crop or termination date at any of the locations in 2020. For 2021, a total of 10 sites across 6 states were planted to a rye cover last fall with planting dates ranging from late-September to mid-November. Cover crop terminations are scheduled to begin in mid- to late-April due to excessive 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
Honey bee pollination experiments. Two colonies were installed near the center of six soybean fields in 2020 to evaluate the effect of bee pollination on soybean yield. Significant honey buildup was observed in these colonies during soybean bloom as the honey bees collected nectar from soybean flowers. A total of 144 plants were hand-harvested from each field to evaluate seed production at different distances from pollinators. Seed counting is complete for three fields. A positive effect of pollinators was observed in one of the largest fields (120 acres), where plants near the honey bee colonies and along field edges with ambient pollinators produced more full pods and heavier seeds than plants that were far away from either of the sources. Interestingly, in the largest field (133 acres), similar effects of pollinator manipulation were observed in 2018 but not in 2020 when the experiment was repeated. In 2020, the grower planted five “wildflower habitats” in this field and broke up the homogeneity of the soybean cover. We hypothesize that the new wildflower habitats attracted additional pollinators and improved pollination in areas where soybean flowers were less likely to be visited by pollinators in the past. In 2021, we plan to install honey bee colonies along field edges, which is more practical for growers and beekeepers than installing bees in field centers. We will compare yield in soybean plants grown in different distances from honey bee colonies.
Floral attractiveness traits and cage experiments. Two bee-attractive and two less attractive varieties, identified from 2019 field surveys, were planted in the horticultural cages with or without honey bees. Cage experiments confirmed that floral attractiveness was primarily driven by floral nectar production. The varieties that produced more nectar were visited more frequently by honey bees than the varieties that produced less nectar in the same cage. Pollination by honey bees increased the percentage of full seed pods by approximately 7%. The effect size did not differ significantly between varieties. We plan to test foraging preferences of honey bees and soybean yield response to bee pollination in 4 – 8 additional varieties with cage experiments in 2021.

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
Pyrethroid insecticides: Data continue to be analyzed comparing efficacy of field applications of pyrethroids to levels of mortality observed in glass-vial assays. These results will help determine out ability to predict efficacy of field sprays based on results of glass-vial assays. Experiments are underway in growth chambers and a greenhouse to assess potential fitness costs of pyrethroid resistance in soybean aphid. These experiments include several insecticide-resistant and insecticide-susceptible populations. Clonal lines of soybean aphid are being established for on-plant assessment of resistance to thiamethoxam.

2.5 Soybean stem borer
Participants: Kevin Rice* (University of Missouri), Robert Wright (University of Nebraska), Raul Villanueva (University of Kentucky) *Project leader
Six field sites were planned to conduct sunflower trap crop evaluation. Two field sites were lost due to COVID travel restrictions during 2020. Two field sites experienced low dectes infestation pressure even though they had previous high dectes numbers. Two field sites experience high dectes populations. Sunflower trap crops at these sites also experienced high infestations from stem boring weevils. We believe the weevils emerge earlier than dectes and outcompete dectes for larvae resources. We will conduct the trap cropping study at 6 field sites in 2021 and quantify weevil infestations.

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
Field testing aphid resistant soybean varieties for commercialization: Field work was conducted at five sites in the summer of 2020. Data for each location has been collected and is being summarized. Aphids were provided to objective leaders for Obj 3.1.2 (Aphid IRM) and Obj 2.4 (insecticide resistance). 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
Insect resistance management for aphid-resistant soybeans: We published a study that supported the positive benefit of refuges in managing virulent aphid frequencies. This study also showed that insecticidal seed treatments had no positive impact on managing virulence. (Esquivel et al. 2021, PMS, doi.org/10.1002/ps.6328). An IRM model for virulence is improving with additional data. We have added data and research from South Dakota State University (A. Varenhorst).

3.2 Soybean breeding for aphid resistance
Participants: Brian Diers* (University of Illinois), Glen Hartman* and Doris Lago-Kutz (USDA-ARS) *Project leaders
Agronomic results along with the phenotypic data on aphid resistance were compared and a manuscript on the release notice for some of this germplasm was started.

Program IV. Insect Monitoring

4.1 Biological control of soybean aphid
Participants: George Heimpel*, with contributions from other project team members *Project leader
Aphelinus numbers were low, 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. More extensive sampling in Minnesota (at least 2 fields per county from 68 counties) found A. certus in 34 counties across the center of the state. We have found no evidence of Aphelinus glycinis from 2017 to 2020. Our studies of A. certus overwintering have shown it is freeze-intolerant, with mortality of 50% at -17°C for 9 days, and our studies are consistent with mummies overwintering insulated in leaf litter under snow. Similar to past years, in a few sites we found a high number of tan braconid mummies, from which emerged the parasitoid Lysiphlebus testaceipes. In late June, when aphids were just beginning to be noticed, an aphid-infested plant on the Saint Paul, Minnesota, campus produced more than 40 tan mummies. In early July, Illinois found 19 tan mummies. Later in the season we found tan mummies in Iowa on July 28 (12 mummies) and August 24 (8 mummies), and at low levels (1 to 3 mummies) in Wisconsin July 28 and August 24 and in Minnesota August 17. For L. testaceipes, similar to 2020 it has been patchy, i.e. a few solitary mummies but also 12 or more mummies from 1 to 3 fields of the 72 sampled each year.

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
All the samples received from May through October 2020 were processed (samples stored in ethanol at -20 Celsius). Aphid data was entered into excel files and the information updated at https://www.eddmaps.org, and shared with our collaborators and extension personnel through https://suctiontrapnetwork.org/data/. Preparation for the coming suction trap season 2021 started with packaging supplies to 33 locations. Supply packages will be shipped to our collaborators during the next reporting period for operation of the suction traps from May 21rst through October 22nd, 2021 (23 weeks).

View uploaded report PDF file

Updated July 19, 2021:
Dear Ed,

Here are the reports from the focus groups my team conducted with farmers, regarding pest management and education/outreach needs and priorities (an executive summary, and the full report). Tom Hunt (Nebraska) and Kevin Rice (Missouri) headed up this project with the assistance of a professional focus group coordinator/analyzer, Dr. Mary Anne Casey.

We worked with farmers, mostly checkoff board members in various states, grouped by geography and also a general group. I think the results are very interesting, and it could be quite beneficial that this feedback has been formally documented. Also, we used several elements of this report to help inform our own proposal to NCSRP this year.

Please share this with your board and anyone else as you see fit.

Regards,
Kelley

View uploaded report PDF file

View uploaded report 2 PDF file

Final Project Results

Updated February 4, 2022:
Program I. Extension/Outreach and Farmer Feedback
1.1 Extension coordination and project deliverables
Participants: Kelley Tilmon* (Ohio State University), with contributions all team members *Project leader
Team members on this project created a number of information deliverables informed by our NCSRP results, past and current. These are detailed in the Project Outputs document (attached), but in summary: between 2019 and 2021 we produced 114 extension publications or other products (e.g., factsheets, podcasts, scouting videos, etc.); 185 extension presentations directly to stakeholders; 58 peer-reviewed journal papers; and 42 scientific meeting presentations. Our team-members were given 7 awards for work related to this project. In addition, we trained 14 graduate students and 2 postdocs, and employed 44 undergraduates on soybean research experiences. We received 35 leveraged grants related to this project, totaling $2.5 million. Several of the region-wide extension outputs planned for this project had to be deferred due to Year 3 budget cuts. However, we had enough cost recovery from canceled conference travel that we were able to print a new second edition of the popular field guide Stink Bugs of the North Central Region, and produce an ID/scouting/threshold quick-card on Defoliators of the North Central Region, with 15,000 hard copies for distribution in North Central states, and available for free online. Work on other planned Year 3 deliverables will resume as part of the new NCSRP entomology project which began in October 2021.

1.2 Determining farmer needs and priorities
Participants: Tom Hunt* (University of Nebraska), Kevin Rice* (University of Missouri) *Project leaders
This objective was focused on farmer participation and feedback to assess needs and thoughts, to help guide future efforts and investments. The findings of this report are intended guide future research and to improve current and create new pest management information, tools, and delivery methods. In early 2021, four focus group interviews were conducted with soybean growers among 11 North Central Region states who were currently or recently members of state soybean associations or boards, plus one focus group interview with crop consultants. The basic purpose of the study was to find about farmers thoughts and feelings regarding soybean insect pests and what they desire from public entomologists to aid in management. Twenty-five participants were recruited, with 22 participating, for a participation rate of 88% (considered excellent for focus groups). Groups in the North Central Region were 1) southeast (IL, MO, OH), 2) southwest (MO, NE, IA), 3) northwest (ND, SD, MN, IA), 4) northeast (WI, MI, IL), and 5) consultants (NE, MI, IL, IN, MN). There were four to five participants in each group.
Dr. Mary Anne Casey, a focus group specialist, conducted the 90-minute Zoom interviews, with Drs. Tom Hunt and Kevin Rice facilitating. Each call was recorded, transcribed, and analyzed using constant comparative methodology. A Final Report (Farmers’ Needs Related to Soybean Insect Pests, 2021, Casey, M.A, K.B. Rice, T.E. Hunt) and Executive Summary were produced and sent to all focus group participants, the NCSRP Board, and other interested parties. Both documents are posted on the NCSRP website. These documents can be considered a Needs Assessment—identifying what types of research, tools, and information are needed by farmers.
https://www.soybeanresearchdata.com/download.aspx?file=Progress2File&name=54114_NCSRP_Focus_Summary.pdf
https://www.soybeanresearchdata.com/download.aspx?file=Progress2File2&name=54114_Farmers_Needs_Related_to_Soybean_Insect_Pests_Report_Final.pdf
For a very brief capsule summary: farmers and crop consultants would like 1) real-time “alerts” about current pest pressure, dispersal direction, and management options, and 2) help from Land Grant Universities and Extension to increase adoption of IPM recommendations because of concerns about the overapplication of pesticides that is leading to resistance.

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
We conducted a survey of soybean fields across 7 states (IA, IL, IN, KS, MI, ND) to (1) determine how extensive insect defoliation of soybean is within the North Central region and (2) to compare methods to quickly and effectively estimate these defoliation levels. Where possible, fields were chosen that were identified as having above-average levels of defoliation. Out of 65 fields sampled a total of 90 times in 2019 and 2020, most had negligible defoliation, and only 1 field reached a level of defoliation that would be considered economically damaging under current recommendations. This survey confirms previous Extension recommendations indicating that, while defoliating insects are commonly found in soybean fields, yield-limiting levels of soybean defoliation caused by insects are rare in the North Central U.S. During our survey, we estimated defoliation using two different methods: collecting individual leaflets and estimating levels of defoliation based on a visual guide (as currently recommended in most extension literature) and taking a visual assessment of the total soybean canopy (a potentially quicker way to sample and compatible with remote sensing approaches). We found that the results obtained using these two methods were similar, though there was variability among samplers. A quick canopy assessment is a viable method for estimating whether a soybean field has reached an economic threshold; however, scout training is still needed to ensure an accurate assessment. Outputs will include better training materials for soybean scouts, including images of soybean canopies with insect defoliation approaching economically relevant levels to show scouts what to look for.

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
The purpose of this study was to evaluate how rye cover crop transitioning to soybean affects insect pest pressure – is pest pressure better, worse, or neutral with regard to the presence of the cover crop and three different termination dates. With 30 site/years of cover crop data spanning seven states (NE, WI, SD, MN, MO, IL, OH), there is sufficient evidence to show that a cereal rye cover crop does not increase the risk of pest pressure when transitioning to soybean. In this study, treatment combinations lead to low as well as exceptionally high amounts of cover crop biomass. This wide variation in biomass is important for representing the wide range of responses that can occur in a rye cover crop to soybean system. Of the insects collected from pitfall traps, none appear to pose a threat to soybean yield. The arthropods collected in the study were placed in broad classification; most are considered to be generalist predators or decomposers which could provide ecosystems services to soybean. However, the value of these arthropods is difficult to determine and was not evaluated in the study.

No significant defoliation of soybean was observed at any of the sites, regardless of the presence or absence of a cover crop. In general, soybean yields were not impacted by the presence of the cover crop. Soybean biomass was measured at a few sites during the V2 stage and in some situations the presence of cover crop significantly reduced total soybean biomass, however, it did not impact final yield.


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

Although soybeans do not require insect pollination to produce a crop, pollination by bees can potentially improve soybean yield while the immense acreage of flowering soybeans can produce substantial nectar flow for honey bees and other pollinators. Our results clearly demonstrate that soybean is an important foraging resource for bees in the agricultural region of Ohio.
We found that honey bee colonies surrounded by more soybeans also gained more weight during soybean bloom. Pollen analysis of honey samples further confirmed that soybean was the predominant nectar source for colonies in large soybean fields. Positive effects of honey bee pollination on soybean yield was only apparent in two fields that were larger than 100 acres. There was no observable effect of honey bee colonies on soybean yield in the smaller fields. The yield benefit could be difficult to detect in small fields due to honey bees’ ability to forage over a long distance (a forager bee can travel over 1 – 2 miles for food). In walk-n cage studies, plants that were caged with honey bees produced up to 7 % more full pods compared to plants in without bees pollination, although the yield difference was not greater in the more attractive varieties.
We find that different soybean varieties can exhibit different levels of attractiveness to bees. Honey bees are more attracted to varieties that produced more nectar whereas sugar concentration, flower size, and flower color have little effect. Nectar production in the bee-attractive varieties was comparable to the values reported for clovers, which are very common forage plant for bees.
Taken together, our findings suggest that soybean is an important nectar source for honey bees. Some varieties are particularly attractive to bees can produce substantial nectar flow to improve honey bee productivity while supporting wild pollinators in the surrounding landscape. Although yield benefits from bee pollination alone was difficult to assess in the field, our controlled experiment showed that honey bee pollination could improve soybean production. Including pollinator management in the soybean cropping system could be the win-win strategy to improve the soybean and honey bee productivity while supporting local pollinators.

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
This project addressed emerging problems related to insecticide resistance in soybean aphid. Since 2015 we have observed field failures of pryrethroids (such as Warrior) in some locations. This objective was to document the level of insecticide resistance in soybean aphids to pyrethroids, and also to examine associated biological characteristics in the aphids. We performed both laboratory and field trials. Field trials performed over multiple years and states confirmed decreased efficacy of field applications of pyrethroids. However, we found that other classes of insecticides still show promising levels of control. Through laboratory research we found that the development of insecticide resistance in soybean aphid is not associated with negative impacts on aphid biology (size, survival, reproduction, etc.). When insecticide resistance is accompanied by fitness costs for the aphids, the aphid lines are more likely to revert back to the insecticide-susceptible state over time if they are not exposed to the insecticide. However, these aphids lacked these fitness costs, making it more likely that they will retain the insecticide resistance into the future. Additional research focused on screening populations of soybean aphid for resistance to neonicotinoid insecticides. The results of our research are being shared with farmers and scientists.

2.5 Soybean stem borer (Dectes)
Participants: Kevin Rice* (University of Missouri), Robert Wright (University of Nebraska), Raul Villanueva (University of Kentucky) *Project leader
This objective was to look at the potential of sunflower to serve as a trap crop for soybean stem borer (Dectes). It was to be performed in 2020 and 2021. Several grower-cooperators with historic Dectes infestations eventually opted out of this study due to Covid-19 or because they rotated out of soybean. However, in Kentucky we discovered a novel, previously undocumented interaction between sunflower, red cocklebur weevil, and Dectes. The weevil interferes with successful development of Dectes inside the plant by preventing Dectes from reaching the root to build its overwintering chamber. Both Dectes and the red cocklebur weevil are attracted to sunflower, but the weevil gets there first, thus interfering with the Dectes life cycle and causing mortality which might eventually decrease populations. Further research is needed to see how this could play into management. In addition, we were fortunate to have a volunteer participant in this study, Dr. David Owens at the University of Delaware. In Delaware, 52-96% of sunflower stems planted near soybean fields showed signs of Dectes infestation, demonstrating the attractiveness of this plant to the pest.

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
The work in this objective will help predict how long aphid-resistant soybeans will remain durable, and also lead to strategies that can delay the increase in virulence (aphids overcoming resistant varieties). Dr. Onstad (Corteva) has developed and fine-tuned a mathematical model to explore the durability of aphid resistance. Dr. Onstad included parameters such as reproductive rate, dispersal to other soybean fields and buckthorn, and fitness differences among virulent and avirulent aphids. This model is in the final stages of development, with a manuscript to be submitted in spring or summer of 2022. During the course of this project, both Dr. O’Neal and Dr. Michel generated additional data for use in the model. One study explored how virulent and avirulent aphids interact on aphid-resistant soybeans and was submitted to the Journal of Economic Entomology. Another study investigated the impact of insecticidal seed treatments on the differential survival and growth of virulent and avirulent aphids. Other data generated included a new assay to identify virulent aphids, which will be further validated in the new NCSRP project.

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 was completed during this project by Brian Diers, et al.: Registration of 64 soybean germplasm lines with all combinations of five soybean aphid resistance genes in two genetic backgrounds. In addition, aphid resistance backcross lines were developed earlier in the project and used in the current time period of this report. A release notice for announcing these isolines has been drafted.
Additionally, through the support of this project we maintained colonies of four known soybean aphid biotypes that overcome resistant varieties. These colonies are critical resources for current and future research. We also tested isogenic lines for resistance to soybean aphid and conducted phenotyping for pyramiding resistant lines. We also evaluated the virulence of soybean aphid clones by using detached leaves and whole plants. Most notably, we found that Rag6 gene alone or in any combination with other genes provides high levels of resistance to the biotypes in our collection, showing good promise for this resistance gene. In adjacent work, we found survivorship of soybean aphid biotypes on winter hosts, common and glossy buckthorn, showing that these virulent biotypes are capable of using the same winter host plants as the non-virulent biotype (and won’t be eliminated from the population by interrupted overwintering).

Program IV. Insect Monitoring
4.1 Biological control of soybean aphid
Participants: George Heimpel*, with contributions from other project team members *Project leader
Biological control of an invasive species (soybean aphid) often occurs through the action of parasitoids, which are stingless wasps that tend to be very specific in the species they target. After much study we released two parasitoid species but neither established locally surviving populations. The parasitoid Aphelinus certus appeared in 2005 and spread rapidly across the soybean growing region of North America, and we have been studying this wasp, trying to determine its effectiveness at controlling soybean aphid. One concern is that, if aphid numbers are low, the parasitoid might go locally extinct, so even with very basic sampling we hope to be able to show that the parasitoid is found where we find the aphid. In the North Central region we found A. certus tends to track the soybean aphid generally, though in 2021 we had 5 states report aphids with no reports of the parasitoid. From our studies in Minnesota, which were much more intensive, we found that even at very low aphid densities the parasitoid was generally active. The low aphid numbers in the years 2019 to 2021 might be a result of parasitism, though other factors have to be considered such as widespread drought (2021) or severe winter cold with no snow cover and delayed planting from a wet spring (2020, Minnesota).

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
The Suction Trap Network maintains insect sampling locations throughout the North Central Region through combined funding from NCSRP, state soybean checkoffs, and private industry. 34 monitoring stations collectively are located in IL, IN, KS, MI, MN, MO, NE, WI, and an un-funded cooperator in Louisiana. This network has allowed us to identify long term trends in soybean aphid biology and can provide a broader idea of where and when outbreaks are likely to occur. In addition, we have a much better understanding of what other pests can be tracked in the monitoring traps, including soybean thrips, and pests of corn, hemp, and wheat. Now we know how rainfall and temperature can affect aerial aphid populations, and how aphids with complex overwintering biology may vary with climate. Besides aphids, we have used the network to monitor soybean thrips which vector several viruses. These findings have implication for understanding microbe diversity in insect pests and their potential use in controlling insect pests. Each summer, trapping data is publicly available at https://suctiontrapnetwork.org/data/ and https://www.eddmaps.org

View uploaded report PDF file

Program I. Extension/Outreach and Farmer Feedback
1.1 Extension coordination and project deliverables
Team members on this project created a number of information deliverables informed by our NCSRP results, past and current. These are detailed in the Project Outputs document (attached), but in summary: between 2019 and 2021 we produced 114 extension publications or other products (e.g., factsheets, podcasts, scouting videos, etc.); 185 extension presentations directly to stakeholders; 58 peer-reviewed journal papers; and 42 scientific meeting presentations. Our team-members were given 7 awards for work related to this project. In addition, we trained 14 graduate students and 2 postdocs, and employed 44 undergraduates on soybean research experiences. We received 35 leveraged grants related to this project, totaling $2.5 million. Several of the region-wide extension outputs planned for this project had to be deferred due to Year 3 budget cuts. However, we had enough cost recovery from canceled conference travel that we were able to print a new second edition of the popular field guide Stink Bugs of the North Central Region, and produce an ID/scouting/threshold quick-card on Defoliators of the North Central Region, with 15,000 hard copies for distribution in North Central states, and available for free online. Work on other planned Year 3 deliverables will resume as part of the new NCSRP entomology project which began in October 2021.
1.2 Determining farmer needs and priorities
We worked with farmers and crop consultants from throughout the North Central Region to conduct focus groups to assess their needs and thoughts, to help guide future efforts and investments. The findings of this report are intended guide future research and to improve current and create new pest management information, tools, and delivery methods. For a very brief capsule summary: farmers and crop consultants would like 1) real-time “alerts” about current pest pressure, dispersal direction, and management options, and 2) help from Land Grant Universities and Extension to increase adoption of IPM recommendations because of concerns about the overapplication of pesticides that is leading to resistance. A report on the outcomes of these focus groups was submitted to the NCSRP for inclusion in the checkoff database, and has also been made available to all focus group participants and other interested parties.
https://www.soybeanresearchdata.com/download.aspx?file=Progress2File&name=54114_NCSRP_Focus_Summary.pdf
https://www.soybeanresearchdata.com/download.aspx?file=Progress2File2&name=54114_Farmers_Needs_Related_to_Soybean_Insect_Pests_Report_Final.pdf

Program II. Insect Management and Profitability
2.1 Management guidelines for defoliating insects
We conducted study of soybean fields in 7 states (1) determine how extensive insect defoliation of soybean is within the North Central region and (2) to compare methods to quickly and effectively estimate these defoliation levels. This survey confirms previous Extension recommendations indicating that, while defoliating insects are commonly found in soybean fields, yield-limiting levels of soybean defoliation caused by insects are rare in the North Central U.S. We tested different methods to assess soybean defoliation. A quick canopy assessment is a viable method for estimating whether a soybean field has reached an economic threshold; however, scout training is still needed to ensure an accurate assessment. Outputs will include better training materials for soybean scouts, including images of soybean canopies with insect defoliation approaching economically relevant levels to show scouts what to look for.

2.2 Cover crops: pest and beneficial insects in cereal rye to soybean transition systems
The purpose of this study was to evaluate how rye cover crop transitioning to soybean affects insect pest pressure – is pest pressure better, worse, or neutral with regard to the presence of the cover crop and three different termination dates. With 30 site/years of cover crop data spanning seven states (NE, WI, SD, MN, MO, IL, OH), there is sufficient evidence to show that a cereal rye cover crop does not increase the risk of pest pressure when transitioning to soybean.

2.3 Pollinators to improve soybean yield
Although soybeans do not require insect pollination to produce a crop, pollination by bees can potentially improve soybean yield while the immense acreage of flowering soybeans can produce substantial nectar flow for honey bees and other pollinators. Our results clearly demonstrate that soybean is an important foraging resource for bees in the agricultural region of Ohio. Taken together, our findings suggest that soybean is an important nectar source for honey bees. Some varieties are particularly attractive to bees can produce substantial nectar flow to improve honey bee productivity while supporting wild pollinators in the surrounding landscape. Although yield benefits from bee pollination alone was difficult to assess in the field, our controlled experiment showed that honey bee pollination could improve soybean production. Including pollinator management in the soybean cropping system could be the win-win strategy to improve the soybean and honey bee productivity while supporting local pollinators.

2.4 Insecticide-resistant soybean aphids
This project addressed emerging problems related to insecticide resistance in soybean aphid. Since 2015 we have observed field failures of pryrethroids (such as Warrior) in some locations. This objective was to document the level of insecticide resistance in soybean aphids to pyrethroids, and also to examine associated biological characteristics in the aphids. In summary, we have documented substantial insecticide resistance to pyrethroids in some aphid populations, which has been contributing to spray failures. However, we found that other classes of insecticides still show promising levels of control.
2.5 Soybean stem borer (Dectes)
This objective was to look at the potential of sunflower to serve as a trap crop for soybean stem borer (Dectes). It was to be performed in 2020 and 2021. Several grower-cooperators with historic Dectes infestations eventually opted out of this study due to Covid-19 or because they rotated out of soybean. However, in Kentucky we discovered a novel, previously undocumented interaction between sunflower, red cocklebur weevil, and Dectes. In short, the cocklebur weevil contributes to Dectes mortality in sunflower, and may prove to be a useful partner in sunflowers as a trap-crop for soybean stem borer.

Program III. Aphid Resistant Varieties and Aphid Virulence Management
3.1 Advancing aphid resistant soybeans through a public-private partnership
The work in this objective will help predict how long aphid-resistant soybeans will remain durable, and also lead to strategies that can delay the increase in virulence (aphids overcoming resistant varieties). Dr. Onstad (Corteva) has developed and fine-tuned a mathematical model to explore the durability of aphid resistance. In addition, we collected additional biological information to be used in the model, which is in the final stages of development. One study explored how virulent and avirulent aphids interact on aphid-resistant soybeans and was submitted to the Journal of Economic Entomology. Another study investigated the impact of insecticidal seed treatments on the differential survival and growth of virulent and avirulent aphids. Other data generated included a new assay to identify virulent aphids, which will be further validated in the new NCSRP project.

3.2 Soybean breeding for aphid resistance
Registration of 64 soybean germplasm lines with all combinations of five soybean aphid resistance genes in two genetic backgrounds, and agronomic and phenotyping was completed during this project by Brian Diers, et al.: Registration of 64 soybean germplasm lines with all combinations of five soybean aphid resistance genes in two genetic backgrounds. In addition, aphid resistance backcross lines were developed earlier in the project and used in the current time period of this report. A release notice for announcing these isolines has been drafted.
Additionally, through the support of this project we maintained colonies of four known soybean aphid biotypes that overcome resistant varieties. These colonies are critical resources for current and future research. We also tested isogenic lines for resistance to soybean aphid and conducted phenotyping for pyramiding resistant lines. A key finding is that the Rag6 gene alone or in any combination with other genes provides high levels of resistance to the biotypes in our collection, showing good promise for this resistance gene.

Program IV. Insect Monitoring
4.1 Biological control of soybean aphid
Biological control of an invasive species (soybean aphid) often occurs through the action of parasitoids, which are stingless wasps that tend to be very specific in the species they target. After much study we released two parasitoid species but neither established locally surviving populations. The parasitoid Aphelinus certus appeared in 2005 and we have documented its rapid spread across the soybean growing region of North America. From our studies in Minnesota, which were much more intensive, we found that even at very low aphid densities the parasitoid was generally active. The low aphid numbers in the years 2019 to 2021 might be a result of parasitism, though other factors have to be considered such as widespread drought (2021) or severe winter cold with no snow cover and delayed planting from a wet spring (2020, Minnesota).

4.2 Monitoring soybean aphids and other soybean insect pests in suction traps
The Suction Trap Network maintains insect sampling locations throughout the North Central Region through combined funding from NCSRP, state soybean checkoffs, and private industry. 34 monitoring stations collectively are located in IL, IN, KS, MI, MN, MO, NE, WI, and an un-funded cooperator in Louisiana. This network has allowed us to identify long term trends in soybean aphid biology and can provide a broader idea of where and when outbreaks are likely to occur. In addition, we have a much better understanding of what other pests can be tracked in the monitoring traps, including soybean thrips, and pests of corn, hemp, and wheat. Besides aphids, we have used the network to monitor soybean thrips which vector several viruses. These findings have implication for understanding microbe diversity in insect pests and their potential use in controlling insect pests. Each summer, trapping data is publicly available at https://suctiontrapnetwork.org/data/ and https://www.eddmaps.org

Benefit to Soybean Farmers

The soybean team in this proposal is multi-disciplinary, with researchers in the fields of entomology, agronomy, and plant pathology. Several of our objectives are coordinated multi-state efforts making our results applicable to a broad geographic area and creating greater research efficiencies through collaboration. The benefit for soybean farmers is that coordinated, collaborative research and outreach is the most efficient way to address insect pest problems that affect their production and profitability.

Performance Metrics

See file upload below

Project Years

YearProject Title (each year)
2024Research and extension on emerging soybean pests in the North Central region
2023Research and extension on emerging soybean pests in the North Central region
2022Research and extension on emerging soybean pests in the North Central Region
2021Soybean Entomology Research and Extension in the North Central Region
2020Soybean Entomology Research and Extension in the North Central Region
2020Soybean Entomology Research and Extension in the North Central Region
2019Soybean Entomology in the North Central Region: Management and Outreach for New and Existing Pests
2018Soybean Entomology in the North Central Region: Management and Outreach for New and Emerging Pests
2017Soybean Entomology in the North Central Region: Management and outreach for New and Existing Pests (2017)
2016Soybean entomology in the North Central region: Management and outreach for new and existing pests