Efficacy of Culicinomyces spp. against Aedes aegypti eggs, larvae and adults.

The aquatic fungal genus Culicinomyces attacks dipteran larvae but little is known about its efficacy against Aedes aegypti. Here we report on the activity of both described species-Culicinomyces clavisporus and Culicinomyces bisporalis-on larvae, eggs and adults, and on trans-stadial transmission. Ten C. clavisporus isolates (ARSEF 372, 582, 644, 706, 964, 1260, 2471, 2478, 2479 and 2480) and C. bisporalis ARSEF 1948 were screened against larvae of this important vector of viral diseases. ARSEF 644, 964 and 2479 had the lowest LC50 (≤3.6 × 105  conidia/ml) after a 3-day exposure and shortest LT50 (≤1.3 days) at 106  conidia/ml against larvae; none of these isolates affected either eggs or adults treated topically with conidia. However, adults fed on a conidial (106  conidia/ml) suspension in 10% sucrose died (≤26.6 ± 3.3% mortality, 5 days after feeding) but no fungal development was detected on dead adults. No pupae or adults obtained following treatment of fourth instar larvae with 105 or 106  conidia/ml showed any indication of fungal presence. C. clavisporus-especially ARSEF 644, 964 and 2479-is the first choice for control of A. aegypti and has high potential in control strategies targeting aquatic larvae.