Emergence of Adult Male Grapholita dimorpha and Periods of Infestation of Apple Orchards in Central Iwate Prefecture, Japan

Abstract

The emergence of adult male Grapholita dimorpha and their periods of infestation of apple orchards in central Iwate Prefecture were investigated from 2006 to 2008. Adult males of the overwintering generation, the first generation,and the second generation were caught using pheromone traps from late May to mid-June, from mid- to late July, and from mid-August to mid-September,respectively. No fruit damage caused by first- and second-generation larvae of this pest was observed in apple orchards, but apples infested by third-generation larvae were observed. Fruit damage caused by third-generation larvae was also observed in an orchard where mating disruption without insecticide spraying was practiced, possibly because second-generation adults flew to the apples of this orchard from other hosts such as plum trees growing nearby.