The Influence of Spray Programs on the Fauna of Apple Orchards in Nova Scotia. XIII. Effects of Perthane on Predators

Abstract

In Nova Scotia, a spray program that integrates chemical and natural control of apple pests has been evolved which is both economical and satisfactory. Among the natural enemies of injurious arthropods that have been favoured by this program are a number of general predators. Further investigation of the ecological principles on which integration is based requires a more intensive knowledge of the factors that influence the densities of these predators. Because of the difficulties of investigating these factors in the orchard, methods of simplifying the predator-prey systems have been sought (Lord, 1956, 1962). These attempts assessed the effects of low dosages of DDT on the interrelationships of phytophagous mites and their natural enemies.