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United States Department of Agriculture

Agricultural Research Service

Title: Sequential Sampling for Adult Coccinellids in Wheat (Changed Titled and Add Accept. Date)

Authors
item Elliott, Norman
item Michels, Gerald - TEXAS A&M UNIVERSITY
item Kieckhefer, Robert - USDA-ARS, RETIRED

Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 12, 1997
Publication Date: N/A

Interpretive Summary: Ladybird beetles are important predators of cereal aphids in wheat in the Great Plains of the United States, for which sampling methods are needed to facilitate improved management. A mathematical relationship between the mean and variance of the number of lady beetles per m**2 in a wheat field was obtained and used to develop a sequential sampling plan to estimate the enumber of lady beetles per m**2 with constant average statistical precisio (standard error/mean). The plan involves conducting a series of 1-minute counts while walking through a field at a constant velocity of 10 meters per minute. After each 1-minute count, a table is consulted to determine if the specified level of precision has been achieved. Results of tests with independent field data indicated that precision achieved when using the plan is close to that specified by the user. The method may prove useful in an integrated pest management system for cereal aphids.

Technical Abstract: Aphidophagous lady beetles are important predators of cereal aphids in wheat in the Great Plains of the United States, for which sampling methods are needed to facilitate improved management. A mathematical relationship between the mean and variance of the number of lady beetles per m**2 in a wheat field was obtained using Taylor's power law. A sequential sampling plan was developed to estimate the number of lady beetles per m**2 with constant average statistical precision (standard error/mean) using an equation relating the number of lady beetles per m**2 to the number of lady beetles per 1-min count and the Taylor's power law relationship. The plan involves conducting a series of 1-min counts while walking through a field at a constant velocity of 10 m per minute. After each 1-min count, sequential sampling stop-lines are consulted to determine if the specified level of precision has been achieved. Two methods, a statistical procedure and a comparison with independent data, were used to verify the accuracy with which the specified level of precision was reached when using the plan. Results indicated that precision achieved when using the plan is close to that specified by the user.

Last Modified: 8/22/2014
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