Oviposition responses of Culex tarsalis and Culex quinquefasciatus to aged Bermuda grass infusions.

Fermented infusions of organic matter are commonly used as baits in traps for gravid female mosquitoes. However, infusions are dynamic, and their effects on mosquito oviposition as their chemical and microbial constituents change over time are not well documented. Bermuda grass infusion fermented for periods of 0-63 days was stimulatory to gravid Culex quinquefasciatus. In contrast, only 5-25-day-old infusion was stimulatory to Culex tarsalis. Standard-aged infusion (7 days old) was as effective or better than infusion of any other age for Cx. tarsalis, whereas Cx. quinquefasciatus exhibited a distinct preference for 2-4-wk-old infusion. The results are discussed in terms of mosquito species' oviposition site preferences and in terms of mosquito surveillance programs.