Tidewater Agricultural Research and Extension Center

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Crop Parasitic Nematode Diagnostics and Applied Research at the Tidewater AREC

Plant parasitic nematodes are a major constraint to agronomic crop production throughout the southeastern United States. However, nematode impacts on crop production are often overlooked and the efficacy of nematode management strategies including host resistance, crop rotation, and chemical or biological control depends on the specific nematode species present and their distributions within fields. Nematode diagnostic services are available at the Virginia Tech campus in Blacksburg, but many growers in the coastal plain region, where a majority of agronomic crops are grown and where sandy soils increase the risk of nematode problems, do not utilize this service due to a lack of awareness, inconvenience, and cost. Even though many growers perceive nematodes as the major “disease” problem impacting their crops, nematode diagnostic services are greatly under-utilized in the state of Virginia. However, Virginia cotton, peanut, and soybean growers indicated they would use nematode diagnostic services if they were available in the southeastern portion of the state.

To fill the gap in nematode diagnostic services and applied research for agronomic crops in Virginia, we established a Nematode Diagnostic Lab at the Tidewater AREC. Since 2016, funding for the nematode lab and nematode management research has been provided by Cotton Incorporated, Virginia Cotton Board, Virginia Soybean Board, and Virginia Corn Board. In addition we have received an IPM Enhancement grant to re-evaluate nematode economic thresholds for agronomic crops in Virginia. Diagnostic and predictive nematode assays are being run for cotton, soybean, and corn growers free of charge as long as commodity boards are able to support the work. In addition, a survey of parasitic nematodes associated with cotton, soybean, and corn cropping systems is being conducted so that the distributions of economically important nematodes can be determined.

In 2018, numerous nematode soil samples were collected and processed at the Tidewater AREC. These included research, survey, and diagnostic samples. Growers were provided with nematode assay results and management recommendations. The most important nematodes in cotton cropping systems were identified and on-farm trials are being conducted in 2019 in cooperation with growers throughout Virginia. In 2018, over 400 nematode soil samples were collected by Extension agents, TAREC staff, growers, and consultants and processed at the Tidewater AREC. For each of these samples, clientele were provided with nematode assay results and management recommendations. Grower awareness of nematode problems (where they are occurring and where they are not) has increased as has grower interest in testing fields prior to applying nematicides.