Bio-efficacy of spinosad against tomato fruit borer (Helicoverpa armigera Hub.) (Lepidoptera: Noctuidae) and its natural enemies

Abstract

The tomato fruit borer, Helicoverpa armigera Hub. is a polyphagous pest attacking cotton, tomato, okra, chilli, cabbage, pigeon pea, gram etc. throughout the world as well as in India. Due to its high fecundity, polyphagous nature, quick adaptation against insecticides, control of this pest with any single potent toxicant for a long time is quiet difficult and rather impossible. So the newer chemicals need to be evaluated for controlling this pest. Field experiment was under taken for two cropping seasons during September - December, 2006 and September - December, 2007 to find out the efficacy of Spinosad 45% SC against tomato fruit borer (H. armigera Hub.) along with Quinalphos 25% EC, Lambda cyhalothrin 5% EC and Cypermethrin 10 EC at ‘Gayespur’ village (Nadia, West-Bengal, India). It was found that Spinosad was effective against H. armigera on tomato at 73 to 84 gm a.i./ha than Quinalphos, Lambda cyhalothrin and Cypermethrin. Spinosad at 73 to 84 gm a.i./ha were very safe to three important predators recorded in tomato field that is, Menochilus sexmaculaus., Syrphus corollae and Chrysoperla carnea.Spinosad is one of such new chemicals which is derived from fermentation broth of soil actinomycetes, Saccharopolyspora spinosa, containing a naturally occurring mixture of spinosyn A and spinosyn D. It is safe to nymphs and adults of the natural enemies. Key words: Spinosad, Helicoverpa armigera, tomato, natural enemies.