Generalist predators undoubtedly play a role in curbing aphid population growth. In agricultural settings, however, this benefit may be largely unrealized until well after aphid pests have increased beyond damaging levels. The ability of the Coccinellid predator Harmonia axyridis (Pallas) to prevent soybean aphid, Aphis glycines Matsumura, populations from reaching damaging levels was investigated in a field cage experiment in southern Wisconsin during July and August, 2001. The effects of H. axyridis larvae at three densities (0.17, 0.42, and 0.67 larvae per square foot) were measured against a control group in which H. axyridis larvae were absent. Soybean aphid numbers were significantly lower in the highest predator density treatment, where mean aphids per trifloiate peaked at 41.4. No differences in soybean aphid densities resulted from H. axyridis predation at the three lowest levels of 0, 0.17, or 0.42 larvae per square foot, where soybean aphid densities peaked at 253.8, 293.1, and 243.8 aphids per trifoliate leaf, respectively. Under the conditions of the experiment, H. axyridis larvae at a density of 0.67 per square foot appear capable of suppressing explosive soybean aphid increase. Results from 2002, currently in progress, will also be discussed.
Species 1: Homoptera Aphididae Aphis glycines (soybean aphid)
Species 2: Coleoptera Coccinellidae Harmonia axyridis (Multicolored Asian Lady Beetle)
Keywords: field cage, predation
Back to Student Competition Ten-Minute Papers, Subsection Ca3. Biological Control
Back to Student Competition 10-minute Paper
Back to The 2002 ESA Annual Meeting and Exhibition