Canadian Forest Service Publications
Resistance against white pine weevil: effects on weevil reproduction and host finding. 1998. Sahota, T.S.; Manville, J.F.; Peet, F.G.; White, E.E.; Ibaraki, A.I.; Nault, J.R. The Canadian Entomologist 130: 337-347.
Issued by: Pacific Forestry Centre
Catalog ID: 5034
Feeding on leaders of resistant Sitka spruce trees, Picea sichensis (Bong.) Carr., led to ovarian regression in white pine weevils, Pissodes strobi Peck., that contained already mature eggs at the time of caging on leaders. Such feeding also led to inhibition or a virtual blockage of ovarian development in weevils that did not contain already mature eggs at the time of caging. Ovarian maturation in such weevils was restored by application of juvenile hormone to female weevils. Effects of three levels of resistance were consistent within the experiments and with the field performance of the tested clones. These results indicate that the effects of resistance were postingestive, i.e., resistance was a form of antibiosis. How antibiosis can cause the weevils to concentrate oviposition on susceptible trees is discussed. Results also provide a means of selecting and ranking resistance of individual spruce trees for tree breeding and reforestation.