This project will build collaborations with farmers across Delaware and Maryland to survey nematode genera in soybean fields across the region. Survey results will be complimented by regional field trials at three locations to assess two seed treatment products versus non-treated seed for nematode control and yield effects. The effect of seed treatments on nematode populations over the course of the season will be monitored by collecting soil samples at planting, 1 month after planting, and at harvest. This project will fund 30% of support for a M.S. student focusing on diseases of soybeans, field supplies and soil samples for three seed treatment trials, and mileage expenses and soil samples for a survey of nematode populations across DE and MD farms. Results from this project will provide insight on the nematode species
present across the region along with efficacy data for potential seed treatment products geared towards nematode control. Project results will be shared through extension publications, field days, news articles, and a regional webinar.

Objective 1: Determine which nematode species are present in soybean acreage across Mid-Atlantic farms.

Objective 2: Screen seed treatment products for efficacy to reduce soybean yield loss from soybean cyst nematode.

Objective 3: Share research findings through extension publications, web outputs, and extension events. Foster regional dialogue concerning nematode sampling observations across DE, MD, PA, and NJ.

Effective communication and outreach are critical components of this proposal. Multiple University resources including the DE Weekly Crop Update, MD Agronomy News, and factsheets will be used to disseminate data. Members of the project are active on social media and will share project updates on platforms like Twitter and Instagram. News outlets like the Delmarva Farmer (circulation: 13,000) will also be notified of project findings. By hosting a nematode focused webinar upon completion of the project, this project aims to bring together researchers from across the region to engage in dialogue on improving understanding and management of nematodes within Mid-Atlantic soybean production.

Updated May 27, 2021:
Fields and grower collaborators have been identified for sampling as part of objective 1 and soil samples will be collected in Aug-Sept. Two field sites were identified for objective 2. One site is in Georgetown, DE and the other in Wye Mills, MD. The DE site has a history of high nematode populations, while the MD site has lower nematode pressure. Plots were planted and stand counts were conducted to examine any differences in emergence among treatments. In June, five plants in row 1 of each plot will be destructively sampled to enumerate female cysts. Soil samples were collected at the time of planting. The next round of samples will be collected at the same time as destructive sampling and the final soil samples will be collected at the end of the season. Updates will be shared throughout the summer in the DE Weekly Crop Update and MD Agronomy news.

Updated June 14, 2022:
Fields and grower collaborators were identified for sampling as part of objective 1 and soil samples were collected in Aug-Sept. Two field sites were identified for objective 2. One site is in Georgetown, DE and the other in Wye Mills, MD. The DE site has a history of high nematode populations, while the MD site has lower nematode pressure. All soil samples have been collected and we are waiting for conditions to allow for harvest. We will post the final report once the yield data is available. Project updates will be shared in a regional webinar November 16, 2021 and in the DE Weekly Crop Update and MD Agronomy news.

View uploaded report

In 2019, the Koehler lab conducted nematode soil sampling across MD and DE to gather a baseline understanding of nematodes currently affecting soybean fields. Soil samples were collected from 60 organic and conventional soybean fields. Within sites sampled, SCN was recovered in 57% of fields, root knot nematode in 17%, lesion nematode in 60%, and dagger nematode in 17%. Based on the widespread finding of nematodes across the region, this project seeks to
expand nematode sampling to an additional 135 field sites over DE and MD in 2021. Growers in the Mid-Atlantic and across the US are in need of more management options for SCN and other nematode genera. In an effort to prepare for future nematode trials, a SCN susceptible soybean cultivar was planted at a field site at the Carvel Research and Education Center in Georgetown, DE with a known history of SCN in 2019. This site is currently being used compare the effects of ILeVo and Saltro to seed with no product applied. So far in the 2020 season, Saltro had lower initial phytotoxicity than ILeVo, and both products had higher emergence rates than non-treated seed. This proposal aims to repeat this trial in 2021 and add two additional field sites to screen product efficacy across multiple environments. Findings from this project will be shared through the University of Delaware Weekly Crop Update and Maryland Agronomy News, which collectively reach over 1400 growers, consultants, and stakeholders while providing a platform to discuss disease concerns and other production issues.