ASPECTS OF THE ECOLOGY OF APPLE LEAF ROLLERS (LEPIDOPTERA: TORTRICIDAE) IN THE OKANAGAN VALLEY, BRITISH COLUMBIA

Abstract

Populations of leaf rollers on apple can be influenced by the proximity of alternative host plants, notably rose, privet, and antelope bush, in part because larval dispersal is common. Indications are that leaf roller population increases caused by parasite decreases are ultimate consequences of pesticide treatments, so that reductions in spray programs will not necessarily cause potential leaf roller pests to become actual pests. The composition of the leaf roller fauna on apple m the Okanagan Valley becomes increasingly complex as the environmental water balance is changed by cultivation and irrigation. There are indications that heavy vehicular traffic can be harmful to leaf rollers and their parasites nearby.