Effect of seed treatment with certain biopesticides on root-knot of chickpea

Abstract

The efficacy of three biopesticides based on Pochonia chlamydosporia, Trichoderma harzianum and Pseudomonas fluorescens was tested on the root-knot of chickpea caused by Meloidogyne spp. under field conditions. The biopesticides were applied to seeds of chickpea cv. BG 256 at the rate of 2 g/kg seed along with the commercial rhizobium. Two thousand J2/kg soil were used as inoculum. Infection by the nematode caused 14 and 15% decline in the dry weight and yield of chickpea, respectively, losses that were avoided when the biopesticides were applied. Dry weight and yield of nematode infected plants were significantly increased by application of P. fluorescens (31 and 34%) and P. chlamydosporia (28 and 25%), respectively. The dry weight and yield of chickpea not inoculated with the nematode was increased by 39 and 36% when P. fluorescens was applied. Seed treatment with fenamiphos resulted in 14 and 18% increase in the dry weight and yield, respectively. Gall formation and egg mass production of root-knot nematodes was decreased by 23 and 18% by the application of P. chlamydosporia against 26 and 19% by fenamiphos. Treatment with P. fluorescens also significantly decreased the number of galls and egg masses, but less than treatment with P. chlamydosporia. Soil populations of the nematodes increased gradually during the growing season in the control plots, but decreased significantly when seeds were treated with P. chlamydosporia or P. fluorescens. Trichoderma harzianum did not significantly affect nematode pathogenesis. Rhizosphere populations of the bioagents increased both in the presence and absence of root-knot nematode.