An IPM module for the management of major insect pests of sugarcane in Indian subtropics

Abstract

This paper describes the evaluation of some environmentally sound tactics developed for raising insect-pests damage free sugarcane crop in subtropical India. Six ecology based approaches were employed: timing irrigation and urea application, mechanical removal of damaging stages of pests and crop residues, earthing up, propping of cane stalks, liberation of egg parasitoid (Trichogramma chilonis) and foliar N application. Effects of these were determined on (i) incidence and intensity of four major insect pests namely, shoot borer (Chilo infuscatellus), top borer (Scirpophaga excerptalis), stalk borer (Chilo auricilius) and black bug (Cavelerius sweeti), (ii) crop growth function , (iii) control efficiency system and (iv) yield and quality of a number of commercial cane cultivars. Timing irrigation (10 day interval) and application of recommended dose of urea and earthing up during formative phase helped the crop escape shoot borer attack as also improved crop vigour in terms of increase in cane height and millable cane number, which ultimately contributed to higher cane yield than that obtained with insecticide treatment. The timely mechanical removal of top borer infested shoots or its egg masses and adults helped reduce the incidence of most damaging third brood alone by over 50 percent in all the cultivars studied. Apart from being completely safe to the environment the technique involves 3-4 times less (Rs. 150-250/ha) expenditure than the chemical treatment ( Rs. 1000-1500/ha ) and may find easy practicability in areas where labour is plentiful and inexpensive and on small family holdings. Innundative releases of egg parasitoid during July-October and the crop production practices like earthing up and propping of cane stalks which help avoid lodging could curtail stalk borer infestation adequately. The incidence and intensity of black bug in ratoon crop was also reduced between 50-70 percent with a concomitant increase in shoot height simply by removal of plant crop residue and foliar N applications. The cumulative use of these tactics resulted in reduced pest damage (below economic injury level), significantly increased yield (22-36% improved productivity), reduced costs of pest control, conservation of natural enemies maintaining resource quality, avoiding environmental and other risks to human and animals, and helped generate employment for poor and needy (mechanical control of top borer insect).