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United States Department of Agriculture

Agricultural Research Service

Title: Sampling Aphidophagous Coccinellidae in Grain Sorghum (Revise Author Listing; Add Accept Date)

Authors
item Michels, Gerald - TEXAS A&M UNIVERSITY
item Elliott, Norman
item Romero, R - AFZC-TMD
item Johnson, Tim - OKLA STATE UNIV

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 1996
Publication Date: N/A

Interpretive Summary: Coccinellids (ladybird beetles) are important aphid predators in grain sorghum fields in the southern Great Plains. Efficient sampling methods for ladybirds in grain sorghum would be a useful step toward incorporating their impact on greenbug populations in the integrated pest management (IPM) decision-making process. We studied five sampling methods for ladybirds in grain sorghum fields in the Texas High Plains. Simply countin the number of ladybirds seen during a prescribed time period was the best overall method from among those we tested. A mathematical model was developed to convert estimates of adult populations obtained by timed counts to estimates of population density. The model accounted for 80% of the variability in the relationship between timed counts and density, and may prove useful in sampling coccinellids in an IPM program for sorghum pests.

Technical Abstract: Coccinellids are important aphid predators in grain sorghum fields in the southern Great Plains. Efficient sampling methods for coccinellids in grain sorghum would be a useful step toward incorporating coccinellid impact on greenbug populations in the IPM decision-making process. In this study, five sampling methods were used for sampling lady beetles in grain sorghum fields in the Texas High Plains. Removal sampling provided accurate estimates of absolute population for adult coccinellids but not for larvae. Sweepnet sampling was not correlated with absolute population for adults or larvae. Timed counts of coccinellids were correlated with absolute population for adults, but results for larvae were inconclusive. A regression model was developed to convert relative estimates of adult populations obtained by timed counts, to estimates of absolute population. The model accounted for 80% of the variability in the relationship between the relative density estimated by timed counts and absolute density estimated by removal sampling.

Last Modified: 11/27/2014
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