The Obliquebanded leafroller (OBLR), Choristoneura rosaceana, is an economically important pest of commercial apples. In order to develop more biologically-based management systems for this pest, it is important to determine the extent to which natural enemies suppress its abundance. Towards this end, we studied parasitism in commercial apple (Malus domestica) and feral gray-dogwood (Cornus racemosa) habitats. The two habitats were used to ascertain whether the relatively simple orchard habitat might lack resources required by some parasitoids. Parasitoid guilds of OBLR were monitored in 2001 and 2002 by placing laboratory-reared larvae on plants, and enclosing the larva with a sleeve cage for 48 hrs. The cages were then removed and larvae were exposed to parasitoids for 4 days after which time the larvae were recollected and reared. In each habitat, OBLR larvae were placed on field-grown plants (apple trees or gray dogwood) and on potted apple trees. At least 14 parasitoid species were obtained from recollected OBLR larvae. Rates of parasitism and parasitoid species composition in the two habitat types and between field-grown plants and potted apple trees were approximately equivalent. Parasitism rates were much higher for the summer OBLR generation compared to the overwintering generation. The high rates of parasitism that we recorded suggest that parasitoids might play a role in OBLR management.
Species 1: Lepidoptera Tortricidae Choristoneura rosaceana (Obliquebanded leafroller)
Keywords: parasitoid, habitat
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