Efficacy and longevity of Bacillus sphaericus 2362 formulations for control of mosquito larvae in dairy wastewater lagoons.

Bacillus sphaericus strain 2362 was evaluated for the control of Culex larvae in dairy wastewater lagoons. Both initial and long-term efficacy were studied. Two primary powder preparations of ABG-6184 yielded mediocre and short-term control at the rates of 0.25 and 0.5 lb/acre (0.26 and 0.56 kg/ha), while level of control and persistence greatly increased as the dosages were increased to 1.0, 2.0 and 4.0 lb/acre (1.12, 2.24 and 4.48 kg/ha). The 1.0 and 2.0 lb/acre rates yielded almost 100% control for 4 weeks and the 4.0 lb/acre rate yielded control (99%) for 49 days or longer. A flowable concentrate preparation (BSP-2) yielded complete initial and persistent control of larvae for 14-21 days at 2.0, 4.0 and 5.0 lb/acre (2.24, 4.49 and 5.6 kg/ha). Granular formulations of B. sphaericus 2362 (ABG-6185) were also evaluated at 2.5, 5.0, 7.5, 10.0 and 20.0 lb/acre (2.8, 5.6, 8.4, 11.2 and 22.4 kg/ha) of the granules. Some of the formulations were more active than the others, yielding excellent initial and persistent control (80% +) for 14-21 days with one treatment.