Evaluation of Bt liquid formulations against gram pod borer, Helicoverpa armigera (Hubner) and spotted pod borer, Maruca vitrata (Geyer) in Pigeonpea

Abstract

A field experiment was conducted during 2012-15 at Regional Agricultural Research Station, Lam, Guntur district, Andhra Pradesh to evaluate the efficacy of Bt liquid formulations and other biopesticides against gram pod borer, Helicoverpa armigera and spotted pod borer, Maruca vitrata in pigeonpea. There were nine treatments [2 strains of Bt liquid formulations each at two doses, two doses of Beauveria bassiana, neem formulation (azadirachtin 1500 ppm), and chemical check] including untreated control. Pooled analysis of three years data revealed that two sprays of NBAII BtG4 @ 2% at fortnight interval significantly superior over other treatments in suppressing the larval population of H. armigera (3.2 larvae / plant) and M. vitrata (5.9 larvae / plant) on pigeonpea and recorded minimum pod damage (3.7 and 11.4%, respectively) with maximum yield (1565 kg/ha). Further, it was also revealed that all Bt liquid formulations and B. bassiana were safe to natural enemy population viz., spiders and coccinellids existing in pigeonpea ecosystem. It is suggested to utilize biopesticides as ecofriendly insecticides for pigeonpea production.