Root-knot Control and Yield Response of Corn with Seed Treatment and Granular Nematicides

Abstract

In Coastal Plain soils of the southeastern United States, the root-knot nematode (RKN) Meloidogyne incognita race 3 causes significant yield loss in corn. Impact of abamectin + thiamethoxam and clothianidin + Bacillus firmus I-1582 nematicide seed treatments along with terbufos granular nematicide on RKN reproduction, plant populations, plant growth, and yield was assessed at two Alabama sites. Thiamethoxam and clothianidin insecticide seed treatments were included as controls. A factorial arranged as split-split plot with year as the main plot, seed treatment as the split plot, and granular nematicide as the split-split-plot treatment was used. Lower plant populations were noted for terbufos-treated corn at one study site. Reduced RKN reproduction was observed with terbufos granular nematicide at both study sites. Fresh seedling weights and yields were usually higher for the terbufos- than non-terbufos-treated corn. At both sites, both nematicide seed treatments and their insecticide seed treatment counterparts had similar plant populations, RKN reproduction rate, and fresh seedling weights. Yield differences were noted at both locations between abamectin + thiamethoxam and thiamethoxam but not clothianidin + Bacillus firmus I-1582 and clothianidin. With mean yield gains up to 13.5%, terbufos was superior to both of the nematicide seed treatments for managing RKN and protecting corn yields. Accepted for publication 19 October 2015. Published 1 November 2015.