Abstract
Altosid SR-10, a slow release formulation of methoprene (isopropyl ll-methoxy-3,7,ll-trimethyl-2,4-dodecadienoate), produced high mortalities when aerially applied to larval populations of Aedes sollicitans (Walker) and Psorophora columbiae (Dyar and Knab) at the rate of 4 fl oz/A (.027 lb AI/A or .03 kg Al/ha) and 2 fl oz/A (.013 lb AI/Aor.015 kg Al/ha) under simulated field conditions. The formulation was persistent enough to provide excellent control even when applied to 2nd and 3rd larval instars. SR-10F (a powdered charcoal formulation of methoprene) was found to be even more persistent than SR-10. Exposure to open sunlight appears to reduce the persistency of both formulations. Baselines of susceptibility to methoprene were determined for 4 species of mosquitoes. The LC50 was .002 parts per billion (ppb) for Aedes epactius (Dyar and Knab), .077 ppb for A. aegypti (L.) .15 ppb for A. sollicitans and .052 ppb for P. columbiae. When methoprene and a protozoan parasite of mosquitoes, Lankesteria culicis (Ross), were used concurrently against populations of A. epactius and A. aegypti, mosquito mortality was increased in the former species but not in the latter. The effect was additive, not synergistic, indicating independence of action. Infectivity and the developmental cycle of L. culicis were not affected when sporocysts (the infective stage of the parasite) were exposed to 5 parts per million (ppm) of methoprene for up to 72 hours. These findings suggest that methoprene and L. culicis are compatible and could be used in combination against certain mosquito species.
Spencer, John Paul (1977). Methoprene and Lankesteria culicis (Ross) (Eugregarinida: Diplocystidae) as compatible mosquito control agents. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -620565.