ALERT Insecticide/Miticide (AC 303,630) is a member of a novel class of insecticides known as pyrroles which have demonstrated a broad spectrum of pesticidal activity on many economic pests worldwide. ALERT is highly active via ingestion, possesses contact activity, and provides moderate residual activity on plants. Initial studies have shown this compound to be equally effective against resistant and susceptible insect and mite species. Results of three years research in California show ALERT to be efficacious in controlling spider mites (Tetranychus spp.) on cotton at rates 0.075 to 0.1 lb ai/a. The addition of crop oil concentrate at 0.25% v/v significantly enhanced acaricidal activity in cotton. Laboratory studies show no evidence of genetic cross-resistance to organophosphate, carbamate, chlorinated hydrocarbon, organotin, and pyrethroid acaricides in twospotted spider mites (Tetranychus urticae). The western predatory mite, Metaseiulus occidentalis, was found to be approximately 120X more tolerant to ALERT compared to susceptible T. urticae and T. pacificus in laboratory bioassays.