Updated August 23, 2021:
Soybean Gall Midge Survey
The majority of the states were able to participate in determining the distribution and severity of soybean gall midge in 2020; however, a few states (Michigan, Ohio, and Indiana) were unable to participate. As a result, Michigan and Ohio have redirected their efforts by producing an informational soybean gall midge postcard which will be sent to approximately 72,000 soybean farmers that will be printed and mailed in April. Nebraska, Iowa, South Dakota, and Minnesota plan to conduct field surveys on the distribution and severity of soybean gall midge during the 2021 season. Nebraska, Iowa, Minnesota, and South Dakota are currently in the midst of field surveys for soybean gall midge. PIs from To date, seven new counties have been identified, with five new counties in Nebraska, one in Iowa, and one in Minnesota. Three of the new counties in Nebraska only had larval presence of sweet clover. Larval counts show a consistent decline in larval number, with the greatest larval number per plant in eastern Nebraska. Field injury generally seems lower this year; however, significant high-pressure sites exist across several research sites in eastern Nebraska.

Adult Emergence Timing and Source
Sites were monitored for emergence beginning on May 2nd, 2021, with the first adult emergence collected on May 31st near Syracuse, NE in Otoe County. East-central Nebraska locations were earlier than other locations, with the exception of a site near Pilger, NE in Stanton County. Of the 31 monitoring sites, 26 sites collected adults, with the first emergence occurring sometime between May 31st and June 14th. The duration of adult emergence from overwintering sites far exceeded the prior two years (2019: 15 days, 2020: 25 days) with approximately 36 days of emergence. The longest duration of emergence occurred in Lancaster County, NE at 44 days. This long duration will pose a significant challenge for management. The vast majority of adults collections occurred in east-central Nebraska, with nearly double the number of overwintering adults collected in 2021 (395) compared to 2020 (192). As in previous years, overwintering adults were only collected from last year’s soybean field with a few individuals from the field margin.

On July 1st, soybean gall midge adults were collected from this year’s soybean at several locations in east-central Nebraska. Adults from this year’s soybean were first collected in Iowa and Minnesota on July 7th and 9th. No first-generation adult emergence has been reported in South Dakota to date. Since emergence occurred on this year’s soybean in Nebraska adults have been found every two days across nearly all of the 14 monitoring sites in east-central Nebraska. In contrast, Iowa, Minnesota, and South Dakota have seen infrequent and erratic emergence of adults. As of July 29th, the number of soybean gall midge adults collected in 2021 (3,423) exceeds the number collected by that date in 2020 (2,378).

Germplasm Screen
Germplasm evaluations are already underway in Nebraska and Iowa. In east-central Nebraska, maturity group I and II soybean lines were found to be 99.8% and 100% infested with larvae for research sites in Lancaster and Saunders County, NE, respectively. The reorganization of germplasm by maturity group has allowed for a series of days of evaluations to allow for a more accurate assessment of plants. Lower infestations were reported in Iowa. GWAS analysis is expected to occur within the next 2-3 months as the data comes in from the germplasm screenings.

Extension Efforts
A NebGuide (G2331) was recently published in Nebraska, highlighting scouting and what is known about the biology and ecology of soybean gall midge. Iowa order a few thousand pocket knives, which have been distributed across the four states (NE, IA, SD, MN) to increase clientele participation in scouting for soybean gall midge. These pocket knives with the NCSRP logo and soybeangallmidge.org website have been well received.

The soybeangallmidge.org continues to grow with 5,578 visits from 4,067 unique visitors with over 8,610 page views. Analytics indicate that approximately 42 countries have accessed the website, with the vast majority of activity coming from the United States. In addition, the alert network through blackboard connect has increased 17% since March, with 442 registered across eight states and Canada. Several field days and events have occurred over the past couple of months, and more are planned for the month of August. It’s unclear if these upcoming events will be in person.

Soybean gall midge multi-state field survey efforts were conducted in North Dakota, Minnesota, Wisconsin, Nebraska, Illinois, Kansas, and to a limited extent in South Dakota and Iowa due to Covid-19 restrictions. Results from the survey found that there were no new state records for the presence of soybean gall midge, however, an expansion of gall midge was observed in existing states (NE, IA, SD, MN, and MO) with extensive injury reported in a number of counties in Nebraska in 2020. Crop injury from soybean gall midge is evident in a number of eastern counties in Nebraska in 2021.

Monitoring for adult emergence of soybean gall midge in the spring shows that overwintering adults are limited to last year's soybean. With three years of data, it is highly unlikely that soybean gall midge overwinters more than one winter in the soil. The first emergence of adults has been relatively stable with adults emerging in mid-June with the exception of 2021 where the first adults emerged on May 31st near Syracuse, Nebraska. The broad and expansive network for adult monitoring for soybean gall midge has resulted in data collected from 28-34 sites across four states for the last couple of years. Of the data collected, the most impactful for management is the number of days that adults emerge from last year's soybean fields. Over the past three years, adults have emerged for an average of 19, 26, and 36 days for 2019, 2020, and 2021, respectively. Such results reinforce the difficulty in managing soybean gall midge and the need for multiple management strategies. Adult numbers collected in east-central Nebraska have shown a significant increase in the number collected over the last three years with approximately 2,700 adults collected in 2019, 4,700 in 2020, and more than 5,000 collected to date in 2021. Season-long adult emergence data also indicated that adult activity is nearly continuous in east-central Nebraska from the first adultemergence in June until early September with overlapping generations during the season.

Germplasm studies evaluating approximately 765 soybean accession lines from the U.S. soybean germplasm for soybean gall midge resistance have shown significant progress with some of these studies being placed at sites where high pressure occurred. In 2020, only 3 accession lines were not infested with soybean gall midge across three sites. In 2021, extensive soybean gall midge pressure occurred at both locations in Nebraska with approximately 99.9% of plots infested. The significant pressure and high frequency of infestation will greatly accelerate the potential to identify any potential resistance in the germplasm over the fall and winter of 2021.

Extension efforts to increase awareness and provide resources have been substantial. A NebGuide (G2331) was recently published in Nebraska, highlighting scouting and what is known about the biology and ecology of soybean gall midge. A couple of thousand pocket knives were purchased and are being distributed across the four states (NE, IA, SD, MN) to increase clientele participation in scouting for soybean gall midge. These pocket knives with the NCSRP logo and soybeangallmidge.org website and have been well received. The website in conjunction with an alert system now spans registered clientele from eight states and Canada. The soybeangallmidge.org website recorded over 4,000 unique visitors spanning 26 counties. Website activity was combined with an online webinar series conducted this past winter with over 3 hours of education content from leading experts on soybean gall midge with over 300 participants.