Field trials with methoprene, temephos, and Bacillus thuringiensis serovar israelensis for the control of larval Culiseta melanura.

In 1992, Altosid (methoprene) pellets, Abate (temephos) 5 CG, and Bactimos (Bacillus thuringiensis serovar israelensis) granules were applied aerially to small field plots within a Culiseta breeding swamp. Aspects measured included the deposition and diffusion of larvicides into larval crypts and effects on larval Culiseta melanura and nontarget aquatic organisms. Formulations were deposited at approximately 50% of application rates. The presence of methoprene in 8 crypt water samples indicated that this larvicide was able to diffuse into Cs. melanura larval crypts. Methoprene was selected for evaluation in a large-scale field trial. In the spring of 1993, methoprene pellets applied to 25% of the study area were an effective larvicide against Cs. melanura. The inhibitory effect on pupae exceeded 81% over a 5-wk posttreatment period.