Evaluation of Soybean Varieties with Avicta for Control of Rotylenchulus Reniformis

Increasing use of soybean in food products and animal feed has driven market prices and demand higher. Soybean acreage in Alabama may expand in the near future and provide a profitable rotation crop to cotton. Reniform nematode: Rotylenchulus reniformis, is an economically significant parasite of cotton; rotation and nematicide use is important to prevent nematode populations from reaching economic thresholds. The objective of this study was to screen five soybean varieties, ranging from susceptible to resistant to nematodes, planted with and without nematicide seed treatment to provide a rotational option for cotton growers. Field trials were planted in a RCBD design in 4 row plots, 25 ft. long with 36in. row spacing and five replications. Untreated varieties were planted on the left two rows and Avicta (0.88mg Abamectin/seed)  treated varieties on the right two rows. Control plots of the varieties were planted in an area without Rotylenchulus reniformis pressure. After 30 days two plants per row were harvested (4 plants per treatment), fresh shoot and root weights were measured and R. reniformis eggs extracted from the roots and enumerated. Yield was collected 155 days after planting. Data was analyzed using SAS 9.4 with Proc Glimmix and the LS-means compared by Tukey’s (P ≤ 0.10) for significant differences. Results indicate that Avicta reduced eggs per gram of root by 425 across all varieties. The Resistant varieties, with and without Avicta, were statistically lower in eggs per gram of root than the untreated susceptible variety. Biomass was not significantly increased by Avicta; control varieties had significantly greater biomass than treated and untreated varieties. Nematicide treated varieties averaged 3 bushels an acre greater than untreated varieties. No statistical differences in yield occurred between untreated varieties and treated counterparts. Control plots averaged 11.5 and 14.5 bushels more than treated and untreated varieties respectively.