Methods for Estimating Orchard Mite Populations, Especially with the Mite Brushing Machine

Abstract

Phytophagous orchard mites have become so troublesome in British Columhia during the last decade that special attention has been given to studies on their ecology and control. An important prerequisite for such studies is an accurate and rapid method of estimating population densities of both the mites and their predators. As some mites are less than a fifth of a millimetre long, it is difficult to determine the numbers of adults present on foliage, quite apart from the eggs and other immature stages. Methods for estimating orchard mite populations developed to date may be classified as either direct, in which the mites are counted on the leaves or estimated, or indirect, in which the mites are removed from the leaves and a known fraction is counted.