Chemical control of Meloidogyne incognita on selected crops

Abstract

Considerable loss of yield in okra, tomato and brinjal due to root-knot nematodes (Meloidogyne incognita) have been reported in India (Bhatti and Jain, 1977). Trials were undertaken at the Indian Institute of Horticultural Research, Hessaraghatta, Bangalore, to estimate the economic value of protection against M. incognita (Kofoid et White) Chitw. given by aldicarb with okra (Abelmoschus esculentus Moench.), brinjal (Solanum melongena L.), french bean (Phaseolus vulgaris L.) and cowpea [Vigna unguiculata (L.) Walp.] grown under field conditions. The trial was laid out in a randomised block consIstmg of six replicates of aldicarb-treated (at rate of 1 kg a.i./ha) or untreated plots (3.0-4.5 m X 3.0 depending on the crop type). Soil samples were taken before treatment to estimate the numbers of M. incognita larvae. Plots were sprayed with carbaryl or endosulfan as required to control various insect pests. Plots were harvested and yield of crops recorded. Aldicarb gave protection against the effects of M. incognita in each of the crops (Table I), this being mainly due to the direct damage caused by the nematode, although in french bean interference with nitrogen fixation by Rhizobium also contributed to the loss of yield. The difference in yield between treated and untreated plots for each of the crops clearly indicates the economic value of the aldicarb application.