Economically important pests usually attack a crop or group of crops over a wide region in which there are geographic, local, and temporal variations in the environment. Effectiveness of any control program will therefore depend on the different responses of the crop, pest, and control organism to this pattern of environment. Usually the environmental heterogeneity is treated as an unavoidable complication in program evaluation, and attempts are made to work with “average” conditions.

Author notes

This paper was presented as part of a symposium “Genetics in Biological Control“ at the annual meeting of the Entomological Society of America, Dallas, Tex., Dec. 2, 1968.