OPTIMIZATION MODEL FOR LYGUS-HESPERUS (HETEROPTERA-MIRIDAE) DAMAGE IN COTTON - ECONOMIC THRESHOLD REVISITED

This paper presents results of a multidisciplinary optimization study on the impact of Lygus hesperas Knight on cotton in the Great Central Valley of California. The results of the empirical studies indicate that lygus bug is not a serious pest of cotton under most circumstances and, furthermore, illustrate why cotton yield enhancements have occurred when their populations have not been controlled. An economic analysis of these results sheds some light on the concept of economic threshold. In particular it is shown how in this case an economic threshold exists even if the costs of pesticides are zero. The theoretical implications of these results are quite general. © 1979, Entomological Society of Canada. All rights reserved.