RALEIGH — Recent findings from a three-year survey of nematode samples by the N.C. Department of Agriculture and Consumer Services point to a wider presence of soybean cyst nematode than previously thought. Evidence of this destructive plant pest has now been found in 57 of the state’s 100 counties, up from 52 counties that were previously identified with the pest.
Anson, Catawba, Chatham, Dare and Lincoln counties were added to the list of SCN-positive counties. Dare had been the only county in the eastern part of the state without previous SCN findings.
SCN causes stunted roots, reducing nitrogen-fixing nodules and increasing the plants’ susceptibility to other soil-borne pathogens. Stunting and yellowing are two of the most common above-ground symptoms noted, Ye said.
“This was one of the most extensive surveys we have done of nematode samples,” said Dr. Weimin Ye, chief of the nematode assay section in the NCDA&CS Agronomic Services Division. “We not only looked at samples that came into the lab, but, additionally, our agronomists collected 244 samples from 28 counties in the western part of the state and also Dare County to give us a comprehensive look across North Carolina.
“It is important we provide farmers with the best agronomic advice possible, and understanding the scope of plant parasitic nematodes can help our agronomists fine-tune the advice they provide,” Ye said.
SCN cannot be eliminated from the soil, but they can be managed to minimize reproduction of the pest and maximize crop yields, Ye added.
Crop rotation and the use of SCN-resistant varieties are the best recommendations for managing the pest. The recommended rotation for control is planting a non-host crop in the first year, followed by a cyst-resistant soybean variety in the second year. That same rotation protocol should follow in year three and four.
The survey was conducted from July 1, 2014, through June 30, 2017, with a total of 100,531 grower samples surveyed over that period. In that group, SCN was found in 21,921 samples, just over 21 percent of the samples. Other highlights of the findings include:
- Johnston (3,462 positive samples), Wayne (3,274), Nash (2,960), Wilson (2,039) and Pasquotank (1,513) had the most SCN-positive samples. Only Wayne falls in the top 10 counties for soybean production.
- Montgomery (831, average of SCN per 500 cc of soil), Bladen (790), Washington (610), Carteret (607) and Harnett (368) counties were found to have the highest SCN population levels.
“Farmers with questions about managing SCN can contact their regional agronomist for advice on a plan for better managing this pest,” said Dr. Colleen Hudak-Wise, director of the Agronomic Division. “It is a free service, and agronomist can often help troubleshoot problems in an early stage, allowing growers to take corrective measures to improve crop yield.”
Regional agronomists are part of the Field Services Section of the department’s Agronomic Services Division. They provide advice on crop fertilization, nutrient management, lime needs, soil testing, plant tissue analysis, use of animal wastes and composts, nematode analysis, and testing of source water and nutrient solutions. To find a regional agronomist for your area, go to www.ncagr.gov/agronomi/rahome.
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