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:GRT00056346
Project Year:2020
Lead Principal Investigator:Kelley Tilmon (The Ohio State University)
Co-Principal Investigators:
Keywords: insects, pests, pollinators, aphid, defoliator, stem borer, cover crop, insecticide resistance

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 2 renewal proposal for a 3-year proposal submitted in FY19. Year 1 progress to date encompasses October 2018 to May 2019, and we are preparing for our first field season on the project (Summer 2019). 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); a new objective focusing on 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; advances in soybean breeding for aphid resistant varieties; 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 the 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 value that honey bees may provide in soybean production (with some preliminary studies documenting the potential for substantial yield improvement). This proposal also incorporates new objectives including the role of cover crops in pest management (whether for good for for ill); 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.

The soybean team in this proposal is multi-disciplinary, with researchers in the fields of entomology, agronomy, and plant breeding. 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. Finally, this proposal incorporates several new researchers in the region (new faculty at the University of Nebraska, University of Illinois, University of Missouri) and also includes established researchers who are new to the project from the University of Wisconsin, University of Kentucky, and Michigan State University – all of which increases our collaborative power and the reach of our results. 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.

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 (*New objective*)

Program III. Aphid Resistant Varieties and Aphid Virulence Management

3.1 Advancing aphid resistant soybeans through a public-private partnership
3.1.1 Field testing aphid resistant soybean varieties for commercialization
3.1.2 Insect Resistance Management for aphid-resistant soybeans
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

Progress of Work

Updated April 28, 2020:
Progress Report (Year 2, October 2019 – March 2020)

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

During the reporting period we began collecting information for an updated Second Edition of the popular Stink Bugs of the North Central Region field guide. We also collected images for a new factsheet on pollinators found in soybean in the region.

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

The focus group procedures were developed (e.g., focus group regions determined, participant selection criteria determined), as well as a focus group script. We have selected the time period of November 2020 (after harvest) to conduct the focus groups. All the above was done under consultation with Dr. Mary Anne Casey, PhD (professional survey/focus group facilitator, University of Minnesota).

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

During the reporting period we analyzed data from the summer: 32 fields in 6 states were sampled for insect defoliation a total of 47 times following a common protocol. Most fields had an overall average of less than 2% defoliation. The highest average defoliation observed across an entire field was 7.1% at a field in Iowa, and the highest average defoliation observed at an individual sampling point (15 leaflets from 5 plants) was 11.5% in the same field. Both of these values are well below the established economic thresholds for defoliating insects in soybean, and none of the sampled fields would have lost yield due to insect defoliation. Ground-level imagery, as well as a limited amount of aerial drone imagery, was collected from these fields to develop sampling aids. Because a graduate student candidate was not identified in Year 1, the objective leader will assume responsibilities for manuscript preparation and data analysis.

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

Data were analyzed from 2019 field work. Cover crop biomass in 2019 varied significantly between sites and termination dates ranging from 75 to 4,600 lb./acre. For the termination treatments, there was no difference observed for soybean yield or plant injury from defoliators; however, arthropods were observed in pitfall traps at all sites. Cover crop sites have been established for the 2020 season. However, Covid-19 has forced a few states to abandon these sites as PIs are unable to carry out late-spring data collection. Other states are continuing but their efforts will be limited due to a loss of summer help, travel restrictions, and continually changing regulations.

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

Pollination: distance experiment. We measured yield at different distances from honey bee hives (field center), midpoints to the edge, and field edges in three fields. Minimal insect pollination was expected near the mid-point of the transect as this would be the farthest point from the honey bee colonies and unmanaged pollinators that are typically most abundant along field edges. In two of three fields we found significantly more seeds/plant on edges than at midpoints, and lower seed set at midpoints than field centers near the hives (though not significantly lower). Our preliminary results showed that supplementing honey bee colonies for soybean pollination can potentially benefit seed production, at least in some varieties. The effect may also be influenced by factors such as field size, varieties, and other field conditions. Pollination: cage experiment. We placed pollinator-exclusion cages in a field to test pollination differences in three soybean varieties (Asgrow AG34X6, AG39X7, and Pioneer 38A98X) with caged and uncaged treatments. This experiment was a collaborated effort with a soybean grower and beekeeper, who noticed more honey bees visiting flowers of AG34X6 than other varieties planted in adjacent fields in the previous year. The three varieties differed significantly in nectar production and sugar concentration. Superior yield from pollination was found in the two varieties with the most/sweetest nectar. Floral attractiveness to bees: we measured nectar during peak bloom in 184 soybean varieties grown as single-variety plots in the same field. Floral attractiveness traits including color, size, nectar volume, and sugar concentration of nectar were measured during bloom. Nectar volume, sugar concentration, and proportion of nectar-producing flowers varied greatly among varieties and within the same variety on different dates, and more bees foraged on varieties with the most nectar. Flower color and size did not appear to affect bee visitation in this experiment. Additional analyses will be performed to examine correlations between floral attractiveness and seed quality traits.

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

Resistance to thiamethoxam: Over 150 aphid clones collected from collaborators around the region were sent to Ohio State University for genetic characterization and whole-plant assays. Two clonal lines were sent from OSU to the University of Nebraska-Lincoln to perform dose-response and diagnostic assays using glass-vial bioassays. UNL attempted to establish the clonal lines and was able to perform four replication of both bioassays with these clonal lines. However, the control mortality was >20%, rendering the data unusable. UNL was not able to perpetuate the clonal lines to repeat the bioassays. Resistance to pyrethroids: Data on efficacy of pyrethroid application for soybean aphid and efficacy of pyrethroids in glass vials from several locations continue to be analyzed to determine if glass vial results can be used to predict field results. Several soybean aphid populations varying in susceptibility (resistance) to pyrethroids are being subjected to greenhouse and laboratory lifetable studies to determine of fitness costs are associated with this insecticide resistance. We are still assessing what the implications of the pandemic are to upcoming planned research.

2.5 Soybean stem borer (*New objective in Year 2*)
Participants: Kevin Rice* (University of Missouri), Robert Wright (University of Nebraska), Raul Villanueva (University of Kentucky) *Project leader

We finalized the protocol for assessing sunflowers as trap crop for dectes stem borer, selected field sites for 2020, and experiment planting is scheduled for May 2020.

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

We have completed the analysis of data from the 2019 field season and shared those results with our colleagues at Corteva/Pioneer. During 2019, aphids were collected and sent to OSU for genetic screening. Only a small percentage of aphids (<2%) were able to survive on Rag plants. Varieties for testing in 2020 have been mailed to cooperators for the 2020 field season. For the IRM project: A model is being developed and parameter values chosen during the first part of 2020. The computer program will be written in spring 2020 with first results evaluating IRM expected by end of summer barring delays. .We completed an analysis exploring how insecticidal seed treatments might be used in the deployment of a refuge strategy. Our data showed that, although insecticidal seed treatment would decrease the overall population, they did not make a significant impact on the frequency of virulent or avirulent biotypes. This manuscript will be submitted for publication in May 2020. We also published a paper that reveals the value of soybean aphid-resistant varieties from both field-data and an economic analysis (Dean et al. 2019), and one revealing that soybean aphid biotypes that can survive on aphid-resistant soybeans are less susceptible to lambda-cyhalothrin (Warrior insecticide) than biotypes that are susceptible to resistant varieties (Valmorbida et al. 2020).

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

Two trials for each soybean aphid biotype were done under greenhouse conditions to test the isogenic lines for resistance to soybean aphid. The phenotyping tests of 31 lines with stack Rag genes 1, 2, 3, 4 and 6 was completed. Data analysis and manuscript 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

As in Year 1, we have requested colleagues in each of the 12 states of the NCSRP to continue sampling for aphids and mummies in soybean fields. We will also request that cuttings of soybeans with mummies be mailed to Saint Paul, MN for identification of primary and hyperparasitoids. In our 2019 field surveys, both aphid and Aphelinus numbers were low. In August Aphelinus were at moderate densities of 0.5 to 1.5 per plant in Minnesota, Wisconsin, and Illinois, and lower numbers were detected in North Dakota, Iowa, and Michigan. These numbers represent limited sampling of 1 to 4 fields in June, July, and August, and Aphelinus was not found until August in any states but Minnesota and Michigan. More extensive sampling in Minnesota (at least 2 fields per county from 56 counties) showed Aphelinus in only 2 counties in July and 13 counties in August. Despite low aphid numbers, we found a surprisingly high number of Lysiphlebus testaceipes parasitisms. Hyperparasitism was undetected in most sites.

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

Our collaborators (33 located in 10 states) sent suction trap samples to the USDA Laboratory in Urbana weekly from the May 17th, 2019 until October 23rd, 2019. Aphid data was entered in EddMaps website to be shared publicly through https://suctiontrapnetwork.org/data/ Additional data of soybean thrips (Neohyadatothrips variabilis), potato leaf hopper (Empoasca fabae), minute pirate bugs (Orius insidiosus) and hover flies (Syrphid species) have been collected and will be analyzed and summarized. Preparation for the coming suction trap season 2020 started in the middle of March. Most of the supplies were ordered, and supply shipments to collaborators will proceed when U of I buildings get unlocked (pandemic). The plan for this coming season is to operate the suction traps from May 22nd through October 23rd, 2020 (23 weeks), barring pandemic-related obstacles.

Final Project Results

Benefit to Soybean Farmers

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 insect management.

Performance Metrics

See chart in proposal

Project Years