Update:
Layman’s Summary
The Soybean Gall Midge Alert Network is an important tool to help farmers stay on top of gall midge levels in their area during the growing season. During this reporting period we identified sites for monitoring in each participating state – we expect to monitor 20 sites this season. We performed routine maintenance in preparation for the season such as emergence cage repair. We also presented emergence data from last season in several in-person extension events and in a soybean gall midge webinar. In the quest for midge-resistant soybean germplasm we analyzed evaluation data from 2022 and decided upon 110 accession lines for further testing in 2023. In the objective looking at how useful tillage and mowing might be for soybean gall midge management, we are planning the experiments for the 2023 growing season. Mowing studies are planned for MN and NE. In NE we will also have a hilling treatment (hilling soil at the base of the plant being an agronomically difficult, but potentially effective, control measure). Regarding tillage, populations of gall midge were low in 2022 and experiments on the value of tillage for management were inconclusive. In the objective to record new detections (range expansion) of gall midge, we have a likely new record from ND (new state) which was inconclusive because of poor sample quality. This will need to be validated in 2023. CropScape data from the 2022 season was available in February 2023 and is being collected to add to the plant injury survey. Monitoring sites are being selected throughout the region for 2023. In addition, we are planning an experts’ tour through KS and MO during the season to meet with farmers and provide additional insights into scouting and surveying in these states.
In the objective to adapt stink bug pheromone lures and sticky traps into an easier scouting method, during 2022 there were 12 states participating in the experiment. During the reporting period we analyzed data from 2022, made minor changes to our protocol, and began preparing for experiments in the 2023 field season.
Regarding the objective on soybean aphid resistance to insecticide, we finished developing the methods to perform bioassays with the insecticides Warrior, Transform, Sefina and Sivanto. We are planning to screen field-collected soybean aphid populations in the summer of 2023. Results to date will be presented at the upcoming Entomological Society of America North Central Branch meeting in Oklahoma City. In addition we have published an updated multistate factsheet on managing insecticide-resistant soybean aphids: https://www.ndsu.edu/agriculture/sites/default/files/2022-04/e1878.pdf (which has also been supplied to SRIN).
In the objective for aphid tolerant soybean varieties, during the reporting period we analyzed data from the 2022 field season [results still pending], consisting of aphids sampled in IA, SD, ND, and OH. Phenotyping indicated a low frequency of virulent aphids. Confirmation of virulence with a few aphid colonies is ongoing and preparations are underway for the 2023 season.
In the soybean pest suction trap monitoring network, suction trap data from the 2022 field season have been entered up to October 2022 to online database https://suctiontrapnetwork.org/data/ and are available to the public. Easter flower thrips, soybean thrips, hover flies and pirate minute bugs data will be analyzed to correlate prey and predator activity patterns. Coordination with collaborators/co-authors for the 2023 monitoring season is in progress.
Finally, in the Outreach objective, the new, second edition of Stink Bugs of the North Central Region has been distributed for winter extension events. We also developed a new exercise for helping farmers determine defoliation levels in soybean, utilizing 3D printed leaves. This skill is important for scouting/management of leaf-feeding insects. We beta-tested the exercise in Ohio this winter and found an average of 35% improvement in the accuracy of assessing defoliation using the leaf tool. SRIN has used our design program to print over 10,000 copies of the soybean defoliation leaf guide, showing the leveraging effect of this investment. The exercise will now be packaged for distribution to extension educators throughout the North Central Region.
Detailed Report
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 sites for 2023 are currently being identified in each state
• We anticipate approximately 20 sites for adult monitoring this coming season
• Emergence cages were repaired, and jars were cleaned for the 2023 season.
• Data on adult emergence was presented at local, regional, and national in-person and webinar-based events.
• 43 new subscribers since October 2022 were added to the Soybean Gall Midge Alert Network
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
• Data from the 2022 season was reviewed to determine the number of entries and type of experiments for the 2023 season.
• Three germplasm field experiments will be conducted during 2023 with two of the experiments occurring in NE, IA, and SD.
• A validation experiment will test 110 accession lines for larval presence and plant injury at two locations in NE and one location in Iowa and South Dakota, with three replications per location. The selection of accession lines for the validation experiment will be based on information collected from previous years. Detailed data collection on a small number of entries (10-15 accession lines) will occur at the same locations as the validation experiment, where a total larval count will be collected on a subsample of plants from each plot. Approximately 50 elite germplasm lines will be tested in Nebraska for larval presence and plant injury.
• Plant injury data will be collected on all experiments at 10-14 internals to calculate an area under the severity progress curve.
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 are planned for MN and NE.
• The mowing study in Nebraska will have hilling treatment added to a portion of the assessment area after the overwintering population emergence to isolate the impact of mowing for that generation.
• Due to the low and sporadic adult emergence, data has been inconclusive on tillage as a viable suppression tactic for overwintering populations.
• This year, an infested stem burial study will be conducted to see if cocoons and adult emergence can be increased. If successful, tillage studies will be implemented in the fall to evaluate this effect.
• The benefits of the stem burial study extend beyond just tillage and allow for a better understanding of other management studies that focus on the soil-dwelling stages of soybean gall midge
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
• Continue to validate the potential new state detection of orange larvae from ND
• Genetics from samples collected across NE and an adjustment of primer concentrations submitted with sequences indicate a strong likelihood that the samples from ND are soybean gall midge.
• GPS points are being generated for KS, MO, IL, WI, and ND for fields at high risk for the presence of SGM for the 2023 season
• Drs. Hodgson and McMechan are planning to tour through KS and MO during the season to provide additional insights into scouting and surveying some fields in these states using their experience from surveys in their respective states.
• CropScape data from the 2022 season was available in February 2023 and is being collected to add to the plant injury survey
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
• During 2022, 12 states participated in this objective totaling 184 weekly comparisons between stink bugs captured on clear sticky traps and in field sweep net samples.
• Total trap captures were not significantly correlated with total field sweep net samples.
• We are currently analyzing the dataset to determine if distance from trap relates to stronger correlations for sweep net captures.
• We are also currently comparing stink bug species that are captured on clear stinky traps among 11 states.
• We will have additional the statistical analysis completed by May.
Program III. Soybean Aphid
3.1 Insecticide Resistance
Participants: Robert Koch* (University), with contributions from all team members *Project leader
• Methods for dose-response bioassays were developed and implemented with the insecticides Warrior, Transform, Sefina and Sivanto for an laboratory population of soybean aphid.
• In summer of 2023, several field-collected populations of soybean aphid will be screened against the three new insecticides using this methodology.
• Results from this NCSRP-funded work focused on insecticide resistance in soybean aphid will be presented at the upcoming meeting of the North Central Branch of the Entomological Society of America in Oklahoma City. In addition, the multistate factsheet on managing insecticide resistant soybean aphid was updated ( https://www.ndsu.edu/agriculture/sites/default/files/2022-04/e1878.pdf ).
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
• Data was collected for defoliation, aphid infestations and sweep nets samples and pod feeding. Sweep net sample identification is ongoing
• Yield was collected at all locations and is currently being analyzed
• Preparation for year 2 is underway
• Aphid samples were collected from IA, SD, ND, and OH. Phenotyping indicated a low frequency of virulent aphids. Confirmation of virulence with a few aphid colonies is ongoing.
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
• The suction trap season for 2023 will start on 12 May and end on 20 October. This represents 23 weeks of suction trap sampling from each of 32 locations. Most of the suction trap supplies have been ordered and currently preparing for packaging and shipping in April. Two undergrad students from University of Illinois have been hired to help with this process, Wesley Hall and Nethra Yuvaraj with majors in Natural Resources and Environmental Sciences, and Biology respectively.
• Aphids suction trap data have been entered up to October 2022 to online database https://suctiontrapnetwork.org/data/ and available to the public.
• Eastern flower thrips, soybean thrips, hover flies and pirate minute bugs data will be analyzed to correlate prey and predator activity patterns. Coordination with collaborators/co-authors is in progress.
• A draft of manuscript about monitoring potato leafhopper is in progress.
Program IV. Extension and Outreach
5.1 Extension Deliverables
Participants: Kelley Tilmon* (Ohio State University), with contributions from all team members *Project leader
• The new, second edition of Stink Bugs of the North Central Region has been distributed for winter extension events.
• We developed a new exercise for helping farmers determine defoliation levels in soybean, utilizing 3D printed leaves. This skill is important for scouting/management of leaf-feeding insects. We beta-tested the exercise in Ohio this winter and found an average of 35% improvement in the accuracy of assessing defoliation using the leaf tool. SRIN has used our design program to print over 10,000 copies of the soybean defoliation leaf guide, showing the leveraging effect of this investment.
Update:
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
• Twenty adult emergence sites were monitored in 2023 across the NE, IA, SD, and MN
• Overwintering adult activity occurred 10 days earlier than anticipated and was reported at 15 of 20 sites.
• Data on adult emergence sent directly to soybean gall midge subscribers via blackboard connect and presented at local and regional events.
• As of September 30th, there are a total of 557 subscribers across 8 states and 2 Canadian provinces on the Soybean Gall Midge Alert Network.
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
• Two germplasm field experiments were conducted in NE, IA, and SD.
o A validation experiment tested 110 accession lines for larval presence and plant injury at two locations in NE and one location in Iowa and South Dakota, with three replications per location.
o Detailed data was collected on a small number of entries (10-15 accession lines) at these same locations, with total larvae counted collected on a subsample of plants in each plot.
o An additional test of 50 elite germplasm lines was conducted in Nebraska for larval presence and plant injury.
• Significant presence of soybean gall midge was reported at both Nebraska locations and in Iowa.
• Data is being analyzed to determine accession lines for the 2024 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.
• In NE, mowing significantly reduced plant injury from soybean gall midge and had significantly greater yield than unmowed areas; however, no differences occurred in the proportion of infested plants or larval number per plant.
• Tillage on the current year’s soybean field reduced plant injury and larval number compared to no-till but wasn’t as effective as hilling soybean. No differences in yield were found between tillage treatments.
• An infested stem burial study was very successful, with over 446 adults emerging from the four treatments.
• Three sites with stem burials were set up in Nebraska on the current year’s soybean to test fall and spring tillage. One site contains 16 plots with the ability to test the use of a moldboard plow at the request of the farmer.
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
• Hundreds of sites were checked across NE, IA, KS, MO, IL, WI, SD, and ND for the detection of soybean gall midge in counties or states where it has not been found.
• Soybean gall midge was detected for the first time in two counties in KS with greater than expected larval counts per plant.
• Samples from ND were sequenced and confirmed as soybean gall midge
• Soybean gall midge was detected in 8 new counties in 2023, bringing the total to 164 counties across 7 states.
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 a second year of field studies across 12 states in the North Central Region comparing stink bug captures on clear sticky traps with in field sweep net sampling.
• Clear sticky traps baited with commercially available pheromone lures were deployed ~ 5 m from four soybean field edges. Each week sweep samples were collected from 20 locations in each field (including edge rows and interior rows) and stink bug captures in sweep samples and traps were recorded.
• Data from both years will be prepared and analyzed during the winter of 2023-2024. A manuscript will be produced and submitted to a peer-reviewed journal in 2024.
Program III. Soybean Aphid
3.1 Insecticide Resistance
Participants: Robert Koch* (University), with contributions from all team members *Project leader
• Results were analyzed and summarized from dose-response bioassays performed on a laboratory population of soybean aphid with the insecticides Transform, Sefina and Sivanto.
• In summer of 2023, six field-collected populations of soybean aphid were established as greenhouse colonies. These were reduced to three colonies that will be used for dose-response bioassays with Transform, Sefina and Sivanto, which are just beginning now.
• Results from this NCSRP-funded work focused on insecticide resistance will be presented in extension meetings in the winter of 2023-2024.
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
• We planted our 2nd year of 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.
• Like last year, scouting for insects occurred 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 will also be receiving sweep samples from collaborators.
• Yield estimates from years 1 and 2 will be averaged and compared once harvest is complete (December/January)
• Sweep samples will be analyzed by Feb 2023.
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
• The total of suction traps that operated so far until October 6th was 30. Michigan ran 2 instead of 3 and Minnesota ran 1 instead of 2.
• The total of suction trap samples processed [rinsed from water and propylene glycol (antifreeze), sorted and counted insects, and stored in 95% at -20 Celsius was 590.
• We have counted so far 137,800 insects, which include aphids, Asian lady beetle, bandedwinged whiteflies, Colaspis, Eastern flower and soybean thrips, European corn borer, flea beetle, green bean leaf beetle, green cloverworm, Japanese beetle, and Northern-Southern and Western rootworms (Fig. 1).
• In addition, we count insect predators such as brown lacewing, green lacewing and insidious flower bugs with a total of 4531 (Fig. 2).
• Whiteflies, ants and hoverflies were sorted out and will be shipped to Michael Crossley (University of Delaware), Jackson Helms, and Scott Clem (University of Georgia) respectively for species identification and respective research studies.
• Soybean aphids caught in suction traps located in Iowa (Ames, Kanawha, Nashua and Sutherland) have been sorted out and will be shipped to Matt O’Neal’s graduate student, Matthew Pfab (Iowa State University) for pyrethroid resistance studies.
• Eastern flower and soybean thrips were sorted out from suction trap locations with both species to be screened for Soybean Vein Necrosis Virus (SVNV) using PCR. These locations included all traps from Illinois (Monmouth, Morris, Orr, and Champaign-II), Indiana [Wanatah (PPAC), Butlerville (SEPAC) and Lafayette (TPAC)], all traps located in Iowa, Kansas (Manhattan), Kentucky (Caldwell), Missouri (Columbia) and Nebraska (Concord). Thirty subsamples of Eastern flower thrips tested negative, and all thirty-five subsamples of soybean thrips tested positive for SVNV.
• Suction trap data are freely available online on the Suction Trap Network web page (https://suctiontrapnetwork.org), hosted by the Center for Invasive Species and Ecosystem Health. This web page provides a real-time snapshot of insect movement during the growing season using an intuitive, graphical format, and most of them show data back to 2018.
Program IV. Extension and Outreach
5.1 Extension Deliverables
Participants: Kelley Tilmon* (Ohio State University), with contributions from all team members *Project leader
• We produced a new edition of the field guide “Stink Bugs of the North Central Region.” During the reporting period, a print run of 3,800 guides was made and copies distributed to 13 Land Grant universities and 15 state checkoff boards. A pdf is also available online at SRIN.
• In Ohio we tested audiences using the “Guide to Defoliation” keychain set and info card at extension meetings, and found that users were on average 30% more accurate at diagnosing soybean defoliation using the guide. This tool can contribute to good scouting for insect defoliation leading to more accurate management decisions.
• The following is an example of the power of leveraging/teamwork to extend project outcomes. Cate Newburg of NCSRP used our “Guide to Defolation” design to print 30,000 leaf set copies for distribution to QSSBs around the country. It is the most asked-for item at farmer events. It has also been featured in checkoff ads, postcards, and signage. A QR code with the material leads clients to the project database for our entomology project, which has received 2740 views, helping to further disseminate information about NCSRP-funded projects.
• The first regional Soybean Gall Midge field day was held at the Eastern Nebraska Research Extension and Education Center near Mead, NE with 101 total attendees that placed a $4,507,592 value to education. Of the respondents, 24% rated the field day as one of the best educational opportunities they had ever attended; all other attendees rated it as above average. The event was sponsored by NCSRP, and data from this project was presented at the field day.
Layman’s Summary
The Soybean Gall Midge Alert Network is an important tool to help farmers stay on top of gall midge levels in their area during the growing season. During this reporting period, we monitored 20 sites, and the first emergence of adults was reported 10 days earlier than anticipated. Data from the emergence network will be presented at several in-person extension events and in a soybean gall midge webinar this winter. Midge-resistant soybean germplasm was collected on 110 accession lines, with 19 studied I greater detail. In the tillage and mowing objective, we saw a reduction in plant injury to soybean adjacent to grass that was mowed compared to unmowed areas. Tilling soil prior to planting soybean also reduced plant injury and the presence of soybean gall midge larvae. Burying soybean gall midge infested soybean stems was an effective way to track adult activity. Three sites were set up with stem burials in Nebraska to test the impact of fall and spring tillage on overwintering larvae in the soil. Field surveys to detect soybean gall midge uncovered a total of eight new counties. Two of these counties were in Kansas which is the first time that soybean gall midge was detected in that state.
In the objective to adapt stink bug pheromone lures and sticky traps into an easier scouting method was conducted across 12 states in 2023. Samples were collected weekly from 20 locations. Data from 2022 and 2023 are being analyzed for a manuscript that will be submitted in 2024.
Regarding the objective on soybean aphid resistance to insecticide, we analyzed and summarized dose-response bioassays on a laboratory population of soybean aphid to Transform, Sefina, and Sivanto. Six field-collected soybean aphid populations were collected during the 2023 season which were reduced to three to test for a dose-response bioassay. Results to date will be presented during the 2023-2024 winter meetings.
In the soybean pest suction trap monitoring network, suction trap data from the 2023 field season have been entered up to October 2023 to the online database https://suctiontrapnetwork.org/data/ and are available to the public. A total of 30 suction traps were in operation during the 2023 season, with a total of 137,800 insects counted so far. Of this total, 4,531 were predators or beneficial insects. Some species, such as whiteflies, ants, and hoverflies, will be sent to Drs. Crossley, Helms, and Clem for species identification and further research. Soybean aphids collected from the suction trap network will be tested for pyrethroid resistance by Dr. O’Neal at Iowa State University.
Finally, in the Outreach objective, we produced a new edition of the field guide “Stink Bugs of the North Central Region.” A total of 3,800 guides were distributed to 13 Land Grant universities and 15 state checkoff boards. A pdf of that guide is also available online at SRIN. In addition, we developed a guide to help farmers determine defoliation levels in soybean with 3D-printed leaves. Users were on average 30% more accurate using the guide.
This skill is important for scouting/management of leaf-feeding insects. We beta-tested the exercise in Ohio this winter and found an average of 35% improvement in the accuracy of assessing defoliation using the leaf tool. SRIN has used our design program to print over 10,000 copies of the soybean defoliation leaf guide, showing the leveraging effect of this investment. The exercise will now be packaged for distribution to extension educators throughout the North Central Region. Cate Newburg of NCSRP used our “Guide to Defolation” design to print 30,000 leaf set copies for distribution to QSSBs around the country. It is the most asked-for item at farmer events. It has also been featured in checkoff ads, postcards, and signage. A QR code with the material leads clients to the project database for our entomology project, which has received 2740 views, helping to further disseminate information about NCSRP-funded projects.
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