Assessment of the use of sex pheromone traps to time chemical control of red bollworm, Diparopsis castanea Hampson (Lepidoptera: Noctuidae) in Malawi

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Abstract
Experiments in Malawi over several seasons indicated that use of sex pheromone baited traps would be an unsatisfactory method for the more efficient timing of insecticide applications against Diparopsis castanea Hmps. Excessive temporal and spatial variation between catches of male moths in pheromone traps and corresponding oviposition by females on cotton renders the method unreliable. Experiments indicated, however, that fewer sprays of insecticide against Diparopsis could be applied without significant loss of yield or quality by spraying when the numbers of eggs of Diparopsis reached 0·25/plant. It is suggested that modification of the existing method of egg scouting on plants offers the best prospect for efficient control of Diparopsis concomitant with the increasing demand by farmers for reduced spraying.