Detection and distribution of the Apple Leaf Midge, Dasineura mali, in Nova Scotia

Abstract

The Apple Leaf Midge (Dasineura mali (Kieffer)) (Diptera: Cecidomyiidae), a foliar pest of apple trees, originated in Europe and was first found in Canada in 1964, when the midge was detected in New Brunswick. Adult midges oviposit on developing apple leaves; the feeding activity of hatched larvae prevents these leaves from unrolling properly, resulting in reduced photosynthesis. Midge infestations on mature trees are not usually problematic. On nursery stock or young trees, however, midge infestations can cause stunting and disrupt tree training. Using data from monitoring records for the period 1990 to 1994, we trace the establishment and spread of the Apple Leaf Midge in Nova Scotia. Results from a 1993 survey of the severity of midge infestations in apple orchards are also presented. Both surveys demonstrate the speed with which the midge spread from the area of initial detection throughout the apple-growing region of Nova Scotia.