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Title: EFFECT OF APHIDS AND THE SURROUNDING LANDSCAPE ON ABUNDANCE OF COCCINELLIDAE IN CORNFIELDS

Author
item Elliott, Norman - Norm
item KIECKHEFER, R - USDA, ARS, NGIRL RETIRED
item Beck, David

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2002
Publication Date: 7/1/2002
Citation: ELLIOTT, N.C., KIECKHEFER, R.W., BECK, D.A. EFFECT OF APHIDS AND THE SURROUNDING LANDSCAPE ON ABUNDANCE OF COCCINELLIDAE IN CORNFIELDS. 2002. BIOLOGICAL CONTROL. V. 24: P. 214-220.

Interpretive Summary: This study was undertaken to determine how the composition and patch size of eastern South Dakota agricultural landscapes and the abundance of aphids in cornfields affected the abundance of adult coccinellids in cornfields. Five landscape variables describing landscape structure (% pasture, % wooded land, % Conservation Reserve Program land, % wetland, and boundary density) and aphid abundance were used as independent variables in constructing stepwise multiple regression models to explain abundance of coccinellids in cornfields. Aphid abundance and landscape variables explained a large proportion of the variation in coccinellid abundance in cornfields. The importance of the study lies in the observation that landscape structure played an important role in determining the abundance of predatory coccinellids in cornfields, a previously unrecognized fact. The results suggest that habitat manipulation practiced at an extra-field (landscape) scale may be effective at improving the biological control of insect pests in agricultural crops by coccinellids.

Technical Abstract: This study was undertaken to determine how the composition and patch size of eastern South Dakota agricultural landscapes and the abundance of aphids in cornfields affected the abundance of adult coccinellids in cornfields. Four species of Coccinellidae were common in cornfields during the three-year study. Five landscape variables (% pasture, % wooded land, % Conservation Reserve Program land, % wetland, and boundary density) and aphid abundance were used as independent variables in constructing stepwise multiple regression models in which abundance of each species of coccinellid were dependent variables. Regression models explained 8 to 45% of the variation in abundance, depending on species of Coccinellidae. Aphid abundance was entered in regression models for three of the four species of Coccinellidae. Aphid abundance had a positive regression coefficient for two species, but the regression coefficient relating abundance of C. maculata to aphid abundance was negative. Each of the five landscape variables was included in a regression model for one or more species. Results are discussed in relation to the biology and ecology of the common species of Coccinellidae inhabiting cornfields in eastern South Dakota.