Insect Predators and Augmentative Biological Control of Balsam Twig Aphid (<I>Mindarus abietinus</I> Koch) (Homoptera: Aphididae) on Christmas Tree Plantations

Abstract

Abstract The balsam twig aphid (Mindarus abietinus Koch) (Homoptera: Aphididae) is a major insect pest of balsam and Fraser firs grown for Christmas trees. Few control methods other than chemical insecticides have been evaluated. In this study, we identified insect predators associated with M. abietinus in three fir Christmas tree fields in Michigan. We also conducted laboratory and field studies to assess the effectiveness of augmentative releases of Chrysoperla rufilabris Burmeister (Neuroptera: Chrysopidae) for M. abietinus control. A diverse complex of predators, primarily generalists including syrphids, coccinellids, and lacewings, was observed on infested trees. Predator abundance was generally low early in spring when M. abietinus fundatrices were present, but predators became more common as sexuparae and later aphid stages appeared. In controlled laboratory tests, C. rufilabris were capable of consuming at least 35 M. abietinus per day, but were able to develop on 10 aphids per day. Average adult ...