POPULATIONS OF SOME MAJOR PESTS AND THEIR NATURAL ENEMIES ON YOUNG AND SEMIDWARF APPLE TREES IN NOVA SCOTIA

Abstract

The population densities of several major apple pests and their natural enemies were studied in an insecticide-free young bearing orchard and in an older orchard of semidwarf trees on an integrated control program. In mature orchards of standard size trees, greater natural mortality occurs than that reported in this study. Over a 5-year period most pests, with notable exceptions, increased rapidly under insecticide-free conditions whereas occasional numerical surges of certain pest species occurred under the mild insecticide program. Insect damage on fruit at harvest averaged 24% in the insecticide-free orchard and 8% in the integrated control orchard which had 2.4 times more harvested fruit.