Time of Attack of the Douglas-Fir Cone Midge in Relationship to Cone Development
Abstract:The Douglas-fir cone midge (Contarinia oregonensis Foote) attacks the cones of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) when they are open for pollination. This period usually lasts a week to 10 days, but may be prolonged by cold weather. The Douglas-fir cone passes through several distinct stages of development each of which is easy to distinguish by direct observation. Thus, it does not seem necessary to make laborious measurements on cone parts to determine stage of development. Observations on the stage of development of other plants such as bracken fern and vine maple may be helpful in determining time of attack of the midge. Hopkins' bioclimatic law appears to be of little use in predicting date of cone opening in the areas studied. The above information will be useful in planning control studies for the Douglas-fir cone midge.
Document Type: Journal Article
Affiliations: Forest Entomologist, Weyerhaeuser Company, Forestry Research Center, Centralia, Wash.
Publication date: May 1, 1963
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