A review of the apple sawfly, Hoplocampa testudinea (Hymenoptera Tenthredinidae).
The apple sawfly (ASF), Hoplocampa testudinea Klug (Hymenoptera Tenthredinidae), attacks only one host plant, the apple tree (Malus domestica Borkh.). It is found in temperate regions of Europe as well as in Eastern North America. The flight of the ASF adults coincides with the bloom of apple trees and larvae develop in fruitlets. As the ASF spends approximately 11 months of its life cycle underground as a pre-pupa or pupa, management of the ASF is possible only during 1 month. The ASF is univoltine and has an obligatory diapause that can be extended to 2, 3 or rarely 4 years. Here key publications about the ASF have been selected for their relevance to the application of Integrated Pest Management programs. Because the ASF is dependent on living and developing tissues and because no oviposition or artificial diet is available for laboratory experimentations, research projects have to be conducted in field or semi-field conditions. The main natural mortality factors are the ichneumonid parasitoids Lathrolestes ensator (Brauns), present in Europe and introduced to Eastern Canada, and Aptesis nigrocincta (Gravenhorst) in Europe. The latter also acts as a hyperparasitoid of L. ensator. Management of the ASF can be based on monitoring adults with sticky traps and with use of a simulation model. Non-insecticidal methods that can be used deliberately in an ASF management program are reviewed, notably nematodes, entomopathogenic fungi, and physical control methods such as cellulose barriers and exclusion netting. The technical and economic reasons preventing widespread implementation of these approaches are discussed.