Rate of Increase in Resistance to DDT in Pink Bollworm Adults1

Abstract

During the past 15 years, resistance to insecticides has made the control of some of our worst insect enemies more difficult. The ability of cotton insect pests to resist insecticides was first noted in the cotton leaf worm, Alabama argillacea (Hubner) (Ivy and Scales 1954). Since 1947 when the widespread use of organic insecticides began, 20 known species of cotton insects and spider mites have developed resistance to insecticides in the United States (Entomology Research Division et al. 1963). There is further evidence that several other cotton insects have developed some tolerance to insecticides formerly used with success for their control.