High tannin (HT) and low tannin (LT) lines were compared for relative control of bollworms when sprayed with Pydrin and Dipel. HT lines increased square feeding but reduced boll feeding significantly. Dipel was more effective on HT plants than on LT plants. The change in feeding behavior and reduced growth rate of larvae are probable causes of increased mortality because of greater exposure to Dipel residues and increased ingestation of articles.