Abstract
European earwigs, Forficula auricularia L., reared on dogfood in an insectary, were released five to six per tree in an experimental block of prebearing apple trees and provided with artificial retreats on the trees and straw spread on the ground. The number of apple aphids, Aphis pomi DeGeer, on these trees declined in 3 weeks from near 500 per tree to less than 50, compared with over 3,000 per tree in an adjacent block kept free of earwigs and nearly 2,000 in a control block.