COMPARATIVE EFFECTS OF INSECT GROWTH-REGULATORS ON LONGEVITY AND MORTALITY OF BEET ARMYWORM (LEPIDOPTERA, NOCTUIDAE) LARVAE

Laboratory bioassays demonstrated the toxic effects of three distinct types of insect growth regulators, diflubenzuron, fenoxycarb, and RH-5 992, against 1- and 6-d-old larvae of the beet armyworm, Spodoptera ex igua (Hubner). Diflubenzuron and RH-5992 were somewhat more active and provided faster knockdown of beet armyworm larvae than did fenoxycarb . RH-5992 and diflubenzuron were 12-21 and 3-5 times more effective, r espectively, against beet armyworm larvae than fenoxycarb. Larvae expo sed to fenoxycarb lived up to 34 d following treatment and continued t o feed. Therefore, fenoxycarb in field settings may not be as acceptab le for controlling larvae of the beet armyworm as are diflubenzuron an d RH-5992.