ABSTRACT
After the U.S. Environmental Protection Agency (EPA) banned mirex and other chlorinated hydrocarbons, an intensive search began for other materials to control pest ants. Insect growth regulators (IGR) are generally non toxic to adult worker ants but provided effective control of certain problem species because they stopped queen egg production. Banks et al. (1983, 1988) showed that the IGR fenoxycarb (Maag Agro-chemicals, Vero Beach, FI) was effective against Solenopsis invicta Buren (see Banks this volume). In recent years, Amdro has become the most popular toxic bait for control of fire ants. However, polygyne S. invicta (multiple nest queens), which is becoming more prevalent, is more difficult to control with Amdro than monogyne S. invicta (one nest queen) (Glancey et al. 1987). Recent field studies show that fenoxycarb effectively controls the polygyne form (Banks et al. unpublished). It kills S. invicta larvae and pupae, and - most importantly - inhibits queen egg production and shifts caste differentiation from worker to sexual forms (Banks et al. 1988). Histological studies of the queen’s reproductive system reveal that fenoxycarb causes regression of the ovaries while completely suppressing the growth of the nurse cells, cytoplasm and follicular epithelium; developing eggs were reabsorbed (Glancey and Banks 1988).
