SAMPLING SYSTEMS FOR EUROPEAN RED MITE, PANONYCHUS ULMI (ACARINA: TETRANYCHIDAE), EGGS ON APPLE IN NOVA SCOTIA

A study was conducted in a mature apple orchard in Nova Scotia to compare the density of eggs of the European red mite, Panonychus ulmi (Koch), over the whole tree to their density on a selected area using a random selection and standard selection technique. Both methods provided nearly equivalent estimates of population densities for generations 2 and 4 but not for generation 3. The population estimates based on sampling from the selected area overestimated the whole tree population. Optimum allocation of sampling resources may be obtained by sampling a small number of clusters from each of a large number of trees.