Field Tests of Systemic Insecticides for the Control of Sitka-Spruce Weevil

Oxydemetonmethyl and Bidrin® (3-hydroxy- N, N -dimethyl- cis -crotonamide dimethyl phosphate) were sprayed on the leading shoots of young Sitka spruce, Picea sitchensis (Bong.) Carr., to determine their effects on Sitka-spruce weevil, Pissodes sitchensis Hopkins. Spring applications made after egg laying, but before the larvae caused appreciable damage, provided good control. Exploratory tests were made also with injected applications of oxydemetonmethyl, Bidrin, demeton, and schradan. Because of limited replication the results of the injection tests can be regarded only as tentative, but both oxydemetonmethyl and Bidrin appeared to provide a good measure of control.