EVALUATION OF THE TREE-BEATING METHOD FOR SAMPLING DEFOLIATING FOREST INSECTS

Abstract

AbstractA procedure for sampling defoliating forest insect larvae by beating them from foliage, used by the Forest Insect and Disease Survey of the Canadian Forestry Service to record population trends and predict future damage and control need in British Columbia, was tested over 150,000 acres on Vancouver Island. The parameters used were average numbers of larvae per collection and percentage positive collections. Results on the test species Acleris gloverana (Wlshm.) and Melanolophia imitata (Wlk.), on host Tsuga heterophylla (Raf.) Sarg., indicated that for low (normal) population levels the present system of choosing three-tree samples along roadsides was satisfactory but that weather conditions markedly affected sample results.