Effects of nematicides on Rotylenchulus reniformis in cotton.

Three field trials were conducted at two locations in Georgia, U.S.A., over three years to compare the efficacy of aldicarb, fenamiphos, 1,3-dichloroproprene (1,3-D), and oxamyl at various rates and combinations on the growth of cotton and population densities of the reniform nematode, Rotylenchulus reniformis. The 1,3-D was injected 30-cm-deep with a single in-row chisel and bedded prior to planting. Aldicarb and fenamiphos were applied in-furrow during planting, and oxamyl was applied as a foliar spray at the first pinhead-square stage of cotton growth. Cotton lint yields varied by location and year but were improved with the aldicar11 (0.59 kg a.i./ha) + oxamyl (0.28 kg a.i./ha) and the 1,3 D (28.1 kg a.i./ha) + aldicarb (0.59 kg a.i./ha) treatments. Lint yields in the fenamiphos treatment did not differ from the controls in four of five tests. Plant stand, height and reniform nematode populations generally did not differ among treatments. Based on data from this investigation, selected chemicals and rates can be recommended to cotton producers to manage damaging levels of the reniform nematode.