Crews from the mosquito and vector control district will begin monitoring pools within the next week or so. That's about two weeks earlier than normal because of the increase in green pools all around town.
Biologists say a single green pool can infect a quarter mile area with mosquitos.
This pool sits in the backyard of a foreclosed home in northwest Fresno and there are probably thousands more throughout Fresno County.
The Fresno mosquito and vector control district says in the last year, the number of known green pools has doubled in its area of the county as shown in these aerial photos.
That has them starting the fight against West Nile about two weeks early this year.
Tim Phillips, Fresno Mosquito and Vector Control District, says "We went from around 440 swimming pools that were unattended green to about 1,000 so we would like to get in sooner and get a handle on them and get them controlled before the season kicks in."
The district says neglected pools are already breeding mosquitos. A crew found these larvae in a green pool this week.
Carole Visveshwara says the pool next door to her home was treated and drained last year after her neighbors lost their house. "It was really terrible over there. It was really bad."
Recent rains have that pool filled up and green once again and mosquitos are already biting. "You want to be able to sit in the backyard. You don't want to get bit up by mosquitos or have any problems," says Visveshwara.
Mosquito and vector control officials plan on bringing in extra crews to visit all of the pools they know about and treat them with mosquito eating fish or chemicals placed on the surface. But they suspect there's even more pools out there they don't know about so they're urging people to call them -- if you see a neglected pool.
After they tackle the pools, officials with the mosquito district will begin spraying ponding basins and other places were water collects.
They say now is also the time to start looking out for water that's collecting in containers around your home which can also breed mosquitos.