CONTROL OF THE YELLOW STEM BORER, SCIRPOPHAGA-INCERTULAS BY MATING DISRUPTION WITH A PVC RESIN FORMULATION OF THE SEX-PHEROMONE OF CHILO-SUPPRESSALIS (LEPIDOPTERA, PYRALIDAE) IN INDIA

A commercially-available, hand-applied PVC resin formulation of the se x pheromone of the striped rice stem borer, Chile suppressalis (Walker ) was used to control the yellow stem borer, Scirpophaga incertulas (W alker), in a 20 ha mating disruption trial in West Bengal, India, in 1 992. Indirect measures of mating disruption were used to compare the p heromone-treated plot with an untreated control plot and a farmers' pr actice plot where a conventional pesticide control regime was practise d. The results showed that the level of 'white head' damage in the phe romone-treated plot was significantly lower than that recorded in othe r treatment plots and that the relative percentage of the larvae of th e two major stem borer species, S. incertulas and Chile polychrysa (Me yrick) found in the region changed from 88% S. incertulas in the farme rs' practice plot to 65% in the pheromone-treated plot. The yields of grain and straw recorded in the pheromone-treated plot were significan tly higher than in the untreated control plot but not significantly di fferent from those recorded in the farmers' practice plot.