Numerous stands of western larch, Larix occidentalis, on the St. Joe, Coeur d'Alene, and Kaniksu National Forests, Idaho, show signs of gradual deterioration following repeated defoliation by larch casebearer, Coleophora Zaricella Hbn. (Tunnock et al. 1969). Stand deterioration can occur after 4 years of continued heavy defoliation. The main symptom...
The larch casebearer, Coleophora laricella (Hubner) was first reported attacking western larch, Larix occidentalis, in Idaho in 1957 (Denton, 1958), 71 years after its introduction into Massachusetts from Europe. The apparent successful regulation of this insect in the eastern U.S. by introduced parasites prompted biological control attempts in the West....
The larch casebearer Coleophora laricella (Hbn.) is now established throughout all western larch stands in Region 1. Population levels have begun to fluctuate in some of the older infested stands; however, it is still on the increase in more recently invaded territory. During the past 2 years work was begun...
A study was made to determine the distribution of parasites of the larch casebearer, Coleophora laricelia, within crowns of western larch, Larix occidentalis. The most common parasites recovered in order of their abundance, were: Agathis pumila (Ratz.), Diciadocerus sp. near westwoodii, Spilochalcis albifrons (Walsh), and MesopoZobus sp. Parasitism by A....
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...
Six fungicides were evaluated to control Botrytis blight of western 41 larch in seedbeds at the Coeur d'Alene Nursery. Fungicides were applied at biweekly intervals during the spring of 1982; test seedlings were inoculated with spores of B. cinerea twice during the evaluation period. Seedling mortality and height were recorded...
Needlecast caused by Meria laricis caused serious losses of 2-0 bareroot western larch during 1983 at the USDA Forest Service Nursery, Coeur d'Alene, Idaho. Cool, wet weather throughout the spring and summer of 1983 was ideal for disease buildup and spread. Control attempts with fungicides were largely unsuccessful because of...