Computer model aids in weevil control

During the late 1950's, the Egyptian alfalfa weevil invaded alfalfa in the desert regions of the southwestern United States. In 1974, it caused in excess of 18 million dollars in damage (1974 California Department of Food and Agriculture Report). This is not surprising as, under certain circumstances, this pest can completely defoliate a crop. In addition, the routine pesticide applications which have been directed against this pest appear to have induced secondary pest outbreaks of other formerly innocuous pests (e.g., aphids, mites and various Lepidoptera), which also, require further pesticide applications to control them. The problems of increasing pesticide applications and the associated costs are so severe that they jeopardize the economical cultivation of alfalfa in the central valley of California.