Host selection by the white pine weevil, Pissodesstrobi Peck: feeding bioassays using host and nonhost plants

Abstract

Thirty-three species of native and exotic conifers in seven genera, five broadleaved trees and shrubs, and a fern species were tested in single-stimulus bioassays to determine the presence or absence of chemical feeding stimulants for Sitka spruce infesting white pine weevils, Pissodesstrobi Peck. Feeding stimulants were present in nearly all conifers tested and absent in all nonconifers. The response varied in intensity among genera, being stronger in Pinus and Picea. Two-choice feeding bioassays demonstrated that the chemical blend inducing maximum feeding response by P. strobi is optimal only in the host Sitka spruce and a few other conifers. Four nonconifers and five conifers, including the weevil's eastern host, eastern white pine, were shown to contain feeding deterrents. It was concluded that the complex mixture of chemicals that determine feeding by P. strobi differs in quality and quantity among the various species tested.