Management of reniform nematode on cowpea, Vigna unguiculata

Abstract

Experiments to control the reniform nematode, Rotylenchulus reniformis, in cowpea, Vigna unguiculata, were conducted in two consecutive years. Two formulations of carbosulfan for seed dressing (3% a.i. w/w) and seed soaking (0.1% a.i. for four hours), and soil applications of carbofuran 3G (1 kg a.i./ha) and neem cake (1,000 kg/ha at planting), were tested as either single or combined treatments. In general, increase of yield and number of Rhizobium nodules/plant and reduction of nematode egg mass index, root and soil populations were greater in the combined treatments than in the single applications. The greatest performance was obtained by dressing the seeds with carbosulfan at 3% a.i. w/w and applying neem cake at 1,000 kg/ha at planting. Negative correlations were observed between egg mass index, root and soil populations of the nematode and all growth indicators and yield. The largest gain was obtained from dressing the seeds with carbosulfan (3% a.i. w/w) and applying 1,000 kg neem cake/ha at planting, while the ratio between additional benefit and treatment cost was greatest from soaking the seeds in 0.1% carbosulfan.