Life History of Dasystoma salicellum Hbn. (Lepidoptera: Oecophoridae), a New Pest of Blueberries in British Columbia

Abstract

Dasystoma salicellum Hbn., a European species first found in North America in 1955, has become a serious pest of commercial highbush blueberries in the lower Fraser Valley of British Columbia.

The species is univoltine, photopositive and has a wide range of hosts. It feeds most often on Salix, Spiraea and Vaccinium. The moths emerge from mid-March to early April and lay eggs in the leaf axils and under bud scales and loose bark. The eggs hatch in late May. The larvae have six instars. The first instars are often dispersed by the wind. Later instars tie new leaves together for shelter, feed on leaves and blossom buds and sometimes enter the early fruit. At harvest the larvae are almost mature and large numbers are dislodged into the crates by picking machines. In September they sometimes defoliate the bushes. In October they pupate within their leaf shelters and drop to the ground with the leaves to overwinter.

Some pupae are destroyed by mould; others are parasitized by Itoplectis quadricingulata (Prov.) and Compsilura concinnata (Mg.). The larvae are parasitized by Macrocentrus iridescens French, and the adults by Tomosvaryella species.