Abstract
Life table study was carried out in the 3rd and 4th, overwintered, generations of Bucculatrix pyrivorella in an insecticide-sprayed orchard. The mortality of the eggs, miners and pupae was remarkably low as compared with that of surface feeders in the 3rd generation. The survivorship curves in the egg and larval stages in the 4th generation were similar to those in the 3rd generation but the pupal mortality tended to be higher in the 4th generation than in the 3rd generation. The larval mortality was considered to be mostly due to insecticide application (mainly fenitrothion), and larvae were attacked by parasites and predators in low intensity. The mortality of overwintered pupae was mostly caused by predation by birds. The quantity of fenitrothion (MEP) deposited on pear leaves tended to decrease as seasons advanced.
