The Portsmouth, Rhode Island Mosquito Control Program used granular Bacillus thuringiensis var. israelensis to successfully control salt marsh mosquitoes in a 9 acre salt marsh while monitoring for, planning and implementing small scale open marsh water management in the marsh. Single season larviciding costs were roughly 4% that of contracted open marsh water management in this marsh.

The insecticidal activity of the delta-endotoxins of 14 Bacillus thuringiensis strains belonging to 12 subspecies was determined against Pieris brassicae, Heliothis virescens, and Spodoptera littoralis. Larvae of P. brassicae were highly susceptible to purified crystals of strains of B. thuringiensis subsp. thuringiensis and B. thuringiensis subsp. morrisoni, whereas H. virescens responded best...