This proposal has programs related to several insect pest problems of emerging importance in the North Central Region, including soybean gall midge, stink bugs, and soybean aphids. In early 2021, we conducted a series of professionally-organized focus group sessions with farmers and crop consultants to assess farmer needs and priorities for pest management research and extension communication. Our objectives are based on the needs-assessment report resulting from this effort [this report is being made available to all soybean checkoff groups]. Farmers identified several concerns. Among these were (1) the emerging threat of soybean gall midge, (2) lack of threshold use for several reasons, but in part because of the time and effort needed to scout, (3) soybean aphid insecticide resistance, (4) the need for pest monitoring and alerts, (5) and the importance of communicating unbiased, research-based pest management information to farmers and their consultants. Other concerns were identified as well, but these are the issues we focused on in this proposal.

Soybean gall midge is an emerging pest which can cause significant damage and which appears to be spreading further each year. When this pest became prominent a few short years ago, nothing was known about its biology or management. With NCSRP and state checkoff support, entomologists on our team were able to rapidly respond to this new threat by learning its life cycle, some basic facts about its biology, and some preliminary information about possible routes of control. Much work remains. In this proposal we have objectives to run a gall midge emergence monitoring program with rapid real-time alerts, which will help farmers know when to scout and when to attempt management. There is an objective to screen landrace germplasm for midge resistance traits to help jump-start breeding efforts for midge-resistant varieties. We are examining both tillage and mowing as cultural controls for gall midge based on promising preliminary data that these approaches can reduce midge damage. Finally, we will perform survey work in new areas to determine the current extent of the gall midges’ range.

Regarding farmers’ concerns that scouting difficulty deters threshold use, we have an objective targeting one of the most difficult scouting problems of all – scouting for stink bugs in later-season soybeans. Stink bugs are a stealth pest that can be managed with insecticide, but which usually go unnoticed because the damage (piercing into seeds with straw-like mouthparts) is hard to detect visually. Scouting involves sweeping dense vegetation throughout the field, which is both difficult and time consuming; few people do it. We will develop a method to monitor stink bugs from the field edge using sticky cards and pheromone lures. Preliminary data suggests this may be a good alternative to sweeping vegetation, and detection and thresholds based on this method will be easy to employ.

This proposal also contains objectives on aphid insecticide resistance, and aphid-resistant varieties. Insecticide resistance is an alarming problem which has been growing since its first detection in 2015. We will determine baseline susceptibility of soybean aphids to newer chemistries, which is the first step in resistance monitoring. We will also screen populations in several states for resistance. Aphid-resistant soybean varieties will become increasingly important as a tool to combat insecticide resistance. As a result of our team’s public-private partnership with Corteva, resistant varieties will soon be available from this major retailer. Our objectives are a new partnership with Corteva, to monitor resistance-breaking virulent aphid biotypes, model the increase of virulence, and to determine the consequences of growing resistant soybeans without supplemental insecticide. In addition, we will continue running a regional aphid and thrips monitoring system.

Finally, we have a dedicated objective to turn project results into extension deliverables to communicate state-of-the-art pest management advice to farmers. All of these objectives will contribute to best-practice pest management in soybean, and contribute positively to farmers’ bottom lines.

Program I. Soybean Gall Midge
1.1 Soybean Gall Midge Alert Network
1.2 Midge-Resistant Soybean Germplasm
1.3 Tillage and Mowing as Control Strategies for Soybean Gall Midge
1.4 New Detection/Injury Survey

Program II. Easier Scouting Methods
2.1 Pheromone-Baited Traps for Stink Bug Monitoring and Thresholds

Program III. Soybean Aphid
3.1 Insecticide Resistance
3.2 Aphid-Resistant Varieties
3.2.1 Impact of growing resistant varieties without insecticide
3.2.2 Frequency and modeling of virulent aphid biotypes
3.3 Suction Trap Network for Monitoring Aphids and Thrips

Program IV. Extension and Outreach
5.1 Extension Deliverables

See chart in proposal text.

Updated January 25, 2023:
During the first reporting period of this new project we prepared for the field season of 2022, for ten new research objectives. This work included devising specific summer research protocols to follow, identifying field sites, having meetings to orient collaborators on research procedures, hiring summer undergraduate help, and obtaining research supplies and materials. The actual research will commence in the spring of 2022.

Outputs during this period: We published a new edition of the fact sheet “Management of Insecticide-resistant Soybean Aphids,” which is currently being printed for distribution for the 2022 field season. We also produced a second edition of the field guide, “Stink Bugs of the North Central Region,” which is likewise being made available for the 2022 field season.

Updated January 25, 2023:
Program I. Soybean Gall Midge

1.1 Soybean Gall Midge Alert Network
Participants: Justin McMechan,* Thomas Hunt, Robert Wright (University of Nebraska); Erin Hodgson (Iowa State University); Bruce Potter, Bob Koch (University of Minnesota); Adam Varenhorst (South Dakota State University). *Project leader

• Adult emergence was monitored on 20 sites across NE, IA, SD, and MN
• First adult emergence from overwintering sites was reported on June 7th in Lancaster County, NE, with the last emergence on July 17th
• Average duration of adult emergence from overwintering sites was 24 days, with the longest duration at 35 days
• In total, 914 adults were collected in 2022, much less than the 5,276 collected in 2021.
• First collection of adults from this year’s soybean was on July 1st, with the last adults collected on September 12th

1.2 Midge-Resistant Soybean Germplasm
Participants: George Graef,* Justin McMechan (University of Nebraska); Erin Hodgson (Iowa State University); Adam Varenhorst (South Dakota State University) *Project leader

• 72 accession lines were tested for resistance at two to three locations in NE, SD, and IA.
• Injury scores were collected throughout the season after first adult emergence with injury from SGM was observed at all four testing sites
• All 72 accession lines had larval presence, with the majority of lines having some level of plant injury.
• A subset of accession lines were collected for larval counts in NE and IA.
• Plots will be harvested along with an analysis of the data to prepare for the 2023 season

1.3 Tillage and Mowing as Control Strategies for Soybean Gall Midge
Participants: Justin McMechan,* Tom Hunt (University of Nebraska); Erin Hodgson (Iowa State University); Bruce Potter, Bob Koch (University of Minnesota); Adam Varenhorst (South Dakota State University) *Project leader

• Mowing studies were conducted in MN and NE with no consistent differences in larval number or plant injury occurred between treatments when sampled in July.
• August samples in Nebraska showed a greater number of larvae for unmowed treatments compared to mowed
• No differences in yield were observed with the mowing in Nebraska
• Pre-season tillage experiments were conducted on a commercial farm near Wall Lake, Iowa. Treatment timings were fall, spring, and fall+spring. Two implements were used for each treatment timing, chisel, and tandem disc.
• Emergence cages captured few overwintering adults, regardless of tillage timing or implement.
• Data are inconclusive if tillage is a viable suppression tactic for overwintering populations.


1.4 New Detection/Injury Survey
Participants: Justin McMechan* (University of Nebraska); Janet Knodel (North Dakota State University); Brian McCornack (Kansas State University); Kevin Rice (University of Missouri), Bryan Jensen (University of Wisconsin); Nicholas Seiter (University of Illinois) *Project leader

• One potential new state detection occurred in ND based on larval presence; however, no genetic analysis could be conducted due to the quality of the samples
• 164 additional GPS points were provided to KS, MO, IL, WI, and ND for fields at high risk for presence of SGM
• A total of 15 new counties were detected across IA (8), SD (5), and NE (2).
• 11 counties were surveyed for SGM next to previously reported counties with no new detections in MN. Soybean injury was low in fields/counties previously reported as infested
• Significant injury to soybean was observed in areas of east central and northeast NE as well as northwest IA

Program II. Easier Scouting Methods

2.1 Pheromone-Baited Traps for Stink Bug Monitoring and Thresholds
Participants: Kevin Rice* (University of Missouri); Kelley Tilmon (Ohio State University); Robert Wright (University of Nebraska); Janet Knodel, Deirdre Prischmann-Voldseth (North Dakota State University); Matt O’Neal (Iowa State University); Robert Koch (University of Minnesota); Brian McCornack (Kansas State University); Nicholas Seiter (University of Illinois); Shawn Conley (University of Wisconsin); Raul Villanueva (University of Kentucky); Christina DiFonzo (Michigan State University); John Tooker (Penn State University) *Project leader

We deployed a clear sticky trap baited with stink bug lures at each edge of soybean fields (4 traps per field). We surveyed traps each week and recorded the number of captured stink bugs. Twenty sweep samples (consisting of 25 sweeps each) were also collected from each field and stink bug abundance recorded. This experiment was deployed in 12 states and each state set up three replicates of the study. Data was collected each week from R3-through R7. Data is currently being collated by PI Rice and 2022 statistical analysis should be completed by Dec.


Program III. Soybean Aphid

3.1 Insecticide Resistance
Participants: Robert Koch* (University), with contributions from all team members *Project leader

1) Due to concerns about potential contamination, a new laboratory colony of insecticide-susceptible soybean aphids was established at the U of MN to ensure integrity of the control population to be used in establishing bioassays. Insecticides and supplies were obtained for performing bioassays.
2) Dose-response bioassays using leaf-dip methodology are being performed for targeted insecticides (Warrior, Sivanto, Transform and Sefina) using the laboratory colony of insecticide-susceptible soybean aphids. The need to reinitiate the laboratory colony of aphids (see previous bullet) set back progress on the bioassays, but the dose-response bioassays will be ready for implementation with field populations in 2023.
3) Results from the previous NCSRP-funded work focused on insecticide resistance in soybean aphid was published in respected scientific journals (see below) and will be presented in winter Extension meetings.

Menger, J.P., A.V. Ribeiro, B.D. Potter, R.L. Koch. 2022. Changepoint analysis of lambda-cyhalothrin efficacy against soybean aphid (Aphis glycines Matsumura): Identifying practical resistance from field efficacy trials. Pest Management Science 78(8): 3638-3643 https://doi.org/10.1002/ps.7006

Menger, J., A.V. Ribeiro, B.D. Potter, I. Valmorbida, E.W. Hodgson, J.J. Knodel and R.L. Koch. 2022. Lack of evidence for fitness costs in soybean aphid (Hemiptera: Aphididae) with resistance to pyrethroid insecticides in the Upper Midwestern United States. Journal of Economic Entomology 115(4): 1191-1202 https://doi.org/10.1093/jee/toac096


3.2 Aphid-Resistant Varieties
Participants: Andy Michel* (Ohio State University); Matt O’Neal* (Iowa State university); Louis Hesler (USDA-ARS South Dakota); Deirdre Prischmann-Voldseth (North Dakota State University) *Project leaders

Our goal for this project is to determine if a late season (R3) insecticide spray has any benefit to aphid resistant soybean (Rag1/Rag3):
• We have planted field trials in ND, SD, NE, IA and OH. These trials included Rag1/Rag3 plants provided by Corteva. We had two treatments: 1) fungicide only spray at R3 and 2) fungicide + insecticide spray at R3
• We scouted for insects at 3 time points: early season, pre-spray and post-spray. Sampling included sweep net, speed scouting for aphids, and defoliation measures
• Soybean aphids have been collected and being reared for phenotype/biotype diagnoses in the Michel lab
• We estimated pod feeding and seed quality prior to harvest
• A few fields have been harvested, but some will be harvested later in the season
• Sweep samples will be sorted during the autumn and winter


3.3 Suction Trap Network for Monitoring Aphids and Thrips
Participants: Nick Seiter* and Doris Lagos-Kutz (University of Illinois); Glen Hartman (USDA-ARS Illinois); with cooperation from other team members *Project leader

• 27 suction traps were consistently sampled the trap season, which started on May 13th, 2022. A suction trap was moved to Caldwell Co, Kentucky on early July under the responsibility of Raul Villanueva, and started to operate on July 15th. Suction trap samples has been regularly mailed in a weekly basis to the USDA-ARS Laboratory located in Urbana, Illinois. A total of 567 suction trap samples have been received up to October 7th.
• The samples have been processed (samples have been drained off the antifreeze and water and stored in ethanol at -20 Celsius). The sampling season will end in October 21rst.
• Besides insect pests of soybean and corn other insects such as predators and invasive species have been monitored. Flying ants have sorted and sent to USDA-ARS (Gainesville, Florida) postdoc, Jackson Helms, who will identify them and use these data to study the effect of landscape on ants’ abundance and diversity. Similarly, hoverflies will be sent to University of Georgia postdoc, Scott Clem, who will identify them to study their migratory patterns. About, 99220 insects have been counted from samples collected between May and October 7th. These data will accordingly be analyzed for further publications.
• Data has been entered in excel files up to October 7th and shared with our collaborators and extension personnel.
• Also, the suction trap data have been shared to the public through https://suctiontrapnetwork.org/data/.


Program IV. Extension and Outreach

5.1 Extension Deliverables
Participants: Kelley Tilmon* (Ohio State University), with contributions from all team members *Project leader

We published a new, second edition of Stink Bugs of the North Central Region. This publication has been shared as a pdf with SRIN, and hard copies have been printed for distribution at winter extension events in each NCSRP member state.

View uploaded report

Updated February 6, 2023:
Reporting period: Year 1 Final: October 1, 2021 to December 31, 2022

Program I. Soybean Gall Midge

1.1 Soybean Gall Midge Alert Network
Participants: Justin McMechan,* Thomas Hunt, Robert Wright (University of Nebraska); Erin Hodgson (Iowa State University); Bruce Potter, Bob Koch (University of Minnesota); Adam Varenhorst (South Dakota State University). *Project leader
• In Year 1, adult gall midge emergence was monitored on 20 sites across NE, IA, SD, and MN
• Adult emergence from overwintering sites happed between June 7 and July 17, with continued capture of adults through September 12. This helps us establish the active window for adult activity and allows comparision among year.
• Collection of gall midge adults in our monitoring system in 2022 was less than 20% what we collected in 2021, showing that there can be large year to year variation in gall midge pressure.


1.2 Midge-Resistant Soybean Germplasm
Participants: George Graef,* Justin McMechan (University of Nebraska); Erin Hodgson (Iowa State University); Adam Varenhorst (South Dakota State University) *Project leader

• We tested 72 accession lines for gall midge resistance at seven locations across three states.
• This allowed us to assess injury which will inform the choice of accession lines for futher advancement in preparation for the 2023 field season.

1.3 Tillage and Mowing as Control Strategies for Soybean Gall Midge
Participants: Justin McMechan,* Tom Hunt (University of Nebraska); Erin Hodgson (Iowa State University); Bruce Potter, Bob Koch (University of Minnesota); Adam Varenhorst (South Dakota State University) *Project leader
• Mowing studies were conducted in MN and NE.
• August samples in Nebraska showed a greater number of larvae for unmowed treatments compared to mowed, though no yield difference were found.
• We conducted chisel and tandem disk tillage experiments with timings in fall, spring, and both fall+spring.
• We found few overwintering adults regardless of tillage timing or implement, probably because 2022 was a relatively low-pressure year in general.
• Data are inconclusive if tillage is a viable suppression tactic for overwintering populations, with futher research needed hopefully under higher-pressure situations.


1.4 New Detection/Injury Survey
Participants: Justin McMechan* (University of Nebraska); Janet Knodel (North Dakota State University); Brian McCornack (Kansas State University); Kevin Rice (University of Missouri), Bryan Jensen (University of Wisconsin); Nicholas Seiter (University of Illinois) *Project leader
• In 2022 there was one possible new state detection in ND, though this finding was inconclusive due to accidental sample destruction. Monitoring will continue in 2023.
• Gall midge was dected in 15 new counties in IA (8), SD (5), and NE (2) showing continued spread.
• Significant injury to soybean was observed in areas of east central and northeast NE as well as northwest IA.
• Preparations are underway for 2023 monitoring.

Program II. Easier Scouting Methods

2.1 Pheromone-Baited Traps for Stink Bug Monitoring and Thresholds
Participants: Kevin Rice* (University of Missouri); Kelley Tilmon (Ohio State University); Robert Wright (University of Nebraska); Janet Knodel, Deirdre Prischmann-Voldseth (North Dakota State University); Matt O’Neal (Iowa State University); Robert Koch (University of Minnesota); Brian McCornack (Kansas State University); Nicholas Seiter (University of Illinois); Shawn Conley (University of Wisconsin); Raul Villanueva (University of Kentucky); Christina DiFonzo (Michigan State University); John Tooker (Penn State University) *Project leader

We conducted this experiment to develop sticky cards and phereomone lures for stink bug sampling. We had locations in 12 states. Data are being analyzed by PI Rice.



Program III. Soybean Aphid

3.1 Insecticide Resistance
Participants: Robert Koch* (University), with contributions from all team members *Project leader

• We conducted dose-response bioassays using Warrior, Sivanto, Transform and Sefina.
• In 2023 we will be ready to conduct dose-response bioassays with field populations.
• Three scientific journal papers have been published based on this project to date.

3.2 Aphid-Resistant Varieties
Participants: Andy Michel* (Ohio State University); Matt O’Neal* (Iowa State university); Louis Hesler (USDA-ARS South Dakota); Deirdre Prischmann-Voldseth (North Dakota State University) *Project leaders

• Our goal for this project is to determine if a late season (R3) insecticide spray has any benefit to aphid resistant soybean (Rag1/Rag3).
• We conducted field trials in five states (ND, SD, NE, IA and OH). Results are being analyzed.
• Soybean aphids have been collected and being reared for phenotype/biotype diagnoses in the Michel lab.


3.3 Suction Trap Network for Monitoring Aphids and Thrips
Participants: Nick Seiter* and Doris Lagos-Kutz (University of Illinois); Glen Hartman (USDA-ARS Illinois); with cooperation from other team members *Project leader

• We monitored 27 suction traps during the 2022 field season, for insect pest of both soybean and corn.
• Data have been shared with several collaborators beyond the bounds of this working group, to help inform other projects.
• Also, the suction trap data have been shared with the public through https://suctiontrapnetwork.org/data/.


Program IV. Extension and Outreach

5.1 Extension Deliverables
Participants: Kelley Tilmon* (Ohio State University), with contributions from all team members *Project leader

We published a new, second edition of Stink Bugs of the North Central Region. This publication has been shared as a pdf with SRIN, and hard copies have been printed for distribution at winter extension events in each NCSRP member state.

Year 1 Summary

Though work on the objectives in this project are ongoing in Year 2, we learned several things in Year 1. For soybean gall midge, we obtained information on the timing of adult activity in the field, which extended from June 7 through September 12. Collection of gall midge adults in our monitoring system in 2022 was less than 20% what we collected in 2021, showing that there can be large year to year variation in gall midge pressure. Gall midge was possibly discovered in one new state (ND) though this will need to be confirmed in 2023. It was also found in 15 new counties in the region, showing that it continues to spread. For the breeding objective (gall-midge resistance) we tested 72 accession lines, some of which will be selected for advancement. For cultural controls, in the first year of testing so far neither mowing nor tillage shows strong control, but overall midge numbers were down in 2022 and work needs to be repeated in years with more gall midge pressure.

We began a project to develop sticky cards with pheromone lures (used to monitor stink bugs in orchards) as a sampling method for stink bugs in soybean. 12 states participated in this objective in 2022, with work to continue in Years 2 and 3.

We are testing four insecticides for the possibility of developing soybean aphid resistance (Warrior, Sivanto, Transform and Sefina). Methods were perfected using a lab colony, with work to begin on field populations in 2023.

In the quest for soybean varieties that are resistant to soybean aphid, our current goal is to determine if a late season (R3) insecticide spray has any benefit to aphid resistant soybean (Rag1/Rag3) by removing tolerant individuals from the population. This is an ongoing objective.

The suction trap network continues to provide region-wide data on insect pests of both corn and soybean that are useful to researchers both within this project and from beyond it. NCSRP funding pays only a portion of the operating costs of this monitoring system, with the full cost being made up from a variety of sources. All of the data from this network are made freely available to the public at https://suctiontrapnetwork.org/data/.

Our main extension deliverable in 2022 was a new, second edition of Stink Bugs of the North Central Region. This publication has been shared as a pdf with SRIN, and hard copies have been printed for distribution at winter extension events in each NCSRP member state.

This project will provide research ultimately leading to management recommendations and educational material on key soybean insect pests and problems in the North Central Region, including soybean gall midge, stink bugs, and insecticide resistance in aphids.