The pink bollworm, Pectinophora gossypiella (Saunders), boll weevil, Anthonomous grandis Boheman and Heliothis spp are pests of major concern in southwestern desert cotton-growing areas of the United States. Mild spring and fall temperatures have encouraged full-season production systems where cotton often remains in the field 10 to 12 months (Willet et al., 1973). Insecticides are generally applied from early July to late September, but late-season bolls remain unprotected since they seldom mature and produce lint. They do, however, serve as a source of host material that produces high overwintering insect populations.