Effect of date of sowing on beanfly infestation of the bean crop

The effect of planting dates on beanfly infestation was investigated in successively planted bean plants during cropping seasons. The population tended to build up in the course of the season following the initial invasion by egg-laying females. Ophiomyia spencerella (Greathead) and Ophiomyia phaseoli (Tryon) were the species of beanflies infesting the bean plants in all seasons. The number of beanfly leaf punctures, eggs, larvae and puparia were more in late planted than early planted bean crop. The bean crop planted late in the season was severely damaged due to the generally higher population levels which had been building up in the course of the season.