FRESNO, Calif. (KSEE) – The life-cycle of a mosquito tends to speed up in warmer temperatures.  Generations of mosquitoes are multiplying faster in the Valley heat and surveillance shows local numbers quickly increasing.

Fresno Mosquito and Vector Control District biologist Chenoa Defreece says, “Our concern of course with increasing temperatures is that mosquitoes become adults quicker, as well as that, helps with the transmission of diseases. As you have more mosquitoes out, they’re biting other individuals, and perpetuating possible disease outbreaks.”

Mosquito monitoring and testing in Fresno County has been positive for West Nile Virus 21 times this year.  A horse in Fresno County also tested positive for the virus.

In Tulare County, 22 tests on mosquitoes came back positive for West Nile Virus as well tests on five birds.

A recent positive test from samples near Clinton and Palm avenues in Fresno prompted late-night spraying of insecticide in the area.

Defreece refers to this control method as adulticide saying, “It’s kind of a last resort. We at Fresno Mosquito prefer to do either physical control, which could be dumping water out so you don’t have the breeding site. We really like to encourage people to use the biological control whether it be our mosquito fish. Additionally, we’ll use a larvacide. It’s actually easier to control mosquitoes at the larval stage than adult.”

Defreece believes mosquitoes will adapt to the very intense heat expected this weekend by waiting until cooler hours to bite.  “They’re very adaptable. It’s very hot here but they might not bite during the daytime, but they will find you.”