Harmonia axyridis (Pallas) is a promising candidate as a biological control agent of aphids in Korea. Using H. axyridis field-collected and maintained in the laboratory (25°¾2°É, RH 40°60%, L:D 16:8), foraging behavior and vertical distribution relative to prey aphid distribution on cucumber were studied.
Foraging behavior (walking speed, walking distance, turning rates) of H. axyridis relative to patch distribution of Aphis gossypii Glover in laboratory condition was investigated. In a plastic arena (¥Õ 9cm), prey were arranged into (1) no prey, (2) even distribution with the same distance, (3) clumped distribution of 50 aphids in one patch , two patches, and four patches. Harmonia axyridis changed their foraging behavior against distribution and existence of A. gossypii. Both H. axyridis adult (°Ï) and 4th larva showed intensive searching behavior within or near a patch but did extensive searching behavior outside the patch.
In the field, vertical distribution of H. axyridis egg, immature and adult against its prey distribution on cucumber, Cucumis sativus var. winter long L. was investigated. Cucumber plants were allowed to natural infestation by A. gossypii from the early stage, and then H. axyridis were released. Young 1st and 2nd larva did not follow the distributional pattern of aphid but 3rd and 4th larva correlated their distribution with prey densities, moving from lower leaves to upper leaves.
Implement of biological control using H. axyridis against aphids in Korean field or greenhouse agriculture are further discussed.
Species 1: Coleoptera Coccinellidae Harmonia axyridis (multicolored Asian lady beettle)
Species 2: Homoptera Aphididae Aphis gossypii (cotton aphid)
Keywords: biological control, Korean
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA