Oviposition attractants could be used for monitoring as well as controlling mosquitoes by attracting them to lay eggs at chosen sites. In the present study, culture filtrates of seven bacterial species were tested for their attractancy against gravid females of
Culex quinquefasciatus
. When their oviposition active indices (OAI) were studied, the culture filtrates of
Bacillus cereus
and
Pseudomonas fluorescens
exhibited oviposition attractancy (OAI = >0.3) at 100 ppm and the OAI were respectively 0.70 and 0.47. Culture filtrates of
B. thuringiensis var.
israelensis (wild type),
B. t. var. israelensis (mutant) and
B. sphaericus showed attractancy at 2000 ppm with OAI of respectively 0.71, 0.59 and 0.68. However, the OAI of
B. megaterium as well as
Azospirillum brasilense
was 0.13 (at 2000 ppm), which was less than 0.3 required to be considered them as attractants. When the oviposition attractancy of the bacterial culture filtrates were compared with that of a known oviposition attractant, p-cresol (at 10 ppm), the culture filtrates of B. t. var. israelensis (wild type) and B. cereus were found to be more active than p-cresol, respectively with 64.2 and 54.3% oviposition.
