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-5992, against 1- and 6-d-old larvae of the beet armyworm, Spodoptera exigua (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, respectively, against beet armyworm larvae than fenoxycarb. Larvae exposed to fenoxycarb lived up to 34 d following treatment and continued to feed. Therefore, fenoxycarb in field settings may not be as acceptable for controlling larvae of the beet armyworm as are diflubenzuron and RH-5992.