Evaluating nematode resistance of 16 Cotton Varieties against Southern Root Knot Nematodes in South Alabama

Field trials conducted in 2025 at the Gulf Coast Research and Extension Center in South Alabama evaluated 16 cotton varieties under low to moderate southern root knot nematode pressure. Varieties differed minimally in stand establishment, biomass, nematode density, and lint yield. Nematicide treatment significantly reduced nematode egg density and increased plant biomass, however, neither stand establishment nor lint yields were improved. While the varieties produced between 1300 and 1700 lbs/acre, lint yields were not significantly affected by either variety or nematicide treatment, reflecting the relatively low nematode pressure at the site. Results indicate that under low root-knot nematode pressure, varietal performance and nematicide application had limited impact on yield, emphasizing the importance of site-specific nematode management decisions.