EFFICACY OF ESFENVALERATE FOR CONTROL OF INSECTS HARMFUL TO SEED PRODUCTION IN DISEASE-RESISTANT WESTERN WHITE PINES
AbstractWe tested the pyrethroid insecticide esfenvalerate in single, double, and triple applications for control of insects affecting seed production of blister rust-resistant western white pine, Pinus monticola Douglas. All treatments increased the proportion of normal seed produced and reduced the proportion of seed damaged by the western conifer seed bug, Leptoglossus occidentalis Heidemann. Only the triple application reduced the proportion of cones killed by the pine cone beetle, Conophthorus ponderosae Hopkins. Other seed-damaging insect species [seed chalcids, Megastigmus sp.; the fir coneworm, Dioryctria abietivorella (Grote); and seedworms, Cydia sp.] were present but in numbers too low to test for insecticide efficacy.