EFFECTS OF PESTICIDE USE ON SPIDERS (ARANEAE) IN QUEBEC APPLE ORCHARDS

Abstract

Abstract In Quebec commercial apple orchards, spider populations are shown to have been depressed numerically by current pest management practices. Hunting species appeared to be more sensitive to insecticides than web-building species. There were large differences in spider distribution among orchards and years, although some consistent patterns were observed. Specimens from the following families were captured: Theridiidae, Linyphiidae, Lycosidae, Araneidae, Erigonidae, Clubionidae, Tetragnathidae, Dictynidae, Salticidae, Philodromidae, and Thomisidae. In orchards treated only for scab control or with only a single insecticide application for apple maggot control, spiders attained their maximal numbers in August. With two treatments for apple maggot control, spiders attained their maximal numbers towards the end of September.