The cranberry girdler, Chrysoteuchia toparia Zeller, has caused increasing damage to tree seedlings in the Coeur d'Alene Nursery since 1980. Heaviest feeding has occurred on the tap roots of 2+0 Douglas-fir stock. By 1983, 8.2 percent of the seedlings examined in seedbeds were injured by this moth. A spray program...
A rare outbreak of hemlock sawfly, Neodiprion tsugae Middleton, was detected in August in drainages near the Canadian border in Idaho infesting several thousand acres. Some stands of western hemlock and subalpine fir were severely defoliated. Understory Engelmann spruce trees were lightly defoliated. The sawfly overwinters in the egg stage...
An evaluation during the summer of 1985 showed that parasites were still exerting control on the larch casebearer on the Flathead NF. Parasitism ranged from 4 to 60 percent and averaged 25.2 percent in the 12 areas surveyed. Four species of parasites were involved. The most abundant was Agathis pumila...
Western spruce budworm defoliated area in the Northern Region has differed significantly across three discrete geographic zones during the past decade. Aerially visible defoliation in northern Idaho increased from 1.7 million acres in 1969 to a high of 2.2 million acres in 1974, and declined to none in 1979. Defoliated...