Vegetos

Abstract

Laboratory and field studies on bioefficacy of locally isolated entomopathogenic nematodes, Steinernema masoodi, S. carpocapsae and Heterorhabditis indica (Rhabditida: Steinernematidae, Heterorhabditidae) were evaluated against legume pod borer, Helicoverpa armigera (Lepidoptera: Noctuidae) infesting chickpea. In laboratory bioassays, S. masoodi [3 Î 10⁹ infective juveniles (IJs)/ha + jaggary 0.5% + glycerine 1% + ujala 0.01%]-sprayed chickpea leaves along with pods were offered to H. armigera larvae soon after spray, the cumulative mortality of 85% was obtained at 72 h in experiment 1 whereas in experiment 2, larval mortality declined from 95% to 75, 55 and 35% at 72 h when treated foliage were offered at 0, 1, 2 and 3 h post-spray. No larval mortality was recorded when treated foliage was fed at 16 and 24 h post-spray in both the experiments. In field experiments conducted at Kanpur and Meerut, reduced pod damage up to 12 and 11% were obtained by the foliar application of S. carpocapsae [3 x 10⁹ IJs/ha + glycerine + ujala] and H. indica [5 x 10⁹ infective juveniles (IJs)/ha + glycerine + teepol], respectively. Correspondingly, maximum grain yield of 26.85 and 21.50 q/ha were harvested by applying the above dosages resulting in 42 and 47% increase in yield over the untreated control.