The large, brown, ugly American cockroach has become an unwelcome house (and pool) guest for many Southern Californians, thanks to this year’s prolonged stretches of hot weather.
Breeding in the warmth and on the hunt for water, roaches are turning up in swimming pools, in bathrooms near drips and along retaining walls, experts and consumers said.
They’re crawling out of sewers at night and moving from house to house as homeowners spray one property just to push the thirsty pests over to the neighbors.
“The weather is the catalyst,” said Ben Garcia, quality assurance specialist with Pasadena-based Dewey Pest Control. “The heat has been driving them out.”
Although cities and counties do not keep track of cockroach populations, entomologists at major pest control companies say calls from panicked or disgusted residents are way up this year.
Sales data from Western Exterminator, which is based in Anaheim and has 36 offices in Southern California, Arizona and Nevada, shows calls complaining about cockroach infestations are up 9.4 percent for the first nine months of this year, over the same period in 2011.
In particular glory are American cockroaches, which usually live in the sewers but are venturing out at night to look for water, said Michael Lawton, an entomologist with Western Exterminator.
Also thriving this year are the smaller, black oriental cockroaches, which are also known as water bugs, he said.
“The higher temperatures will affect their growing process and they’ll do better,” Lawton said. “Their metabolism increases and they can develop faster.”
Chatworth resident Jackie Greig, writing on the NBC4 Facebook page, said this is the first year she has had a cockroach problem at her San Fernando Valley home.
"We've already been sprayed twice, and they're still here," Greig wrote. "I'm at my wits end!"
While both breeds normally stay outside, many are coming into homes, drawn by water and warm temperatures in houses where the air conditioning is not cranked up too high.
“These are creatures that are needing water – that’s why you find them living underneath sinks where water would be available,” said Lila Higgins, manager for citizen science and live animals at the Los Angeles Museum of Natural History.
“These American cockroaches are using our homes because they’ve got some food there,” Higgins said. “There’s water in faucets and hoses, and they like to find the dark places to hide at night – in cavities and walls, and places behind refrigerators.”
Roaches are nocturnal, and most are more active on warm nights than on cool ones, experts said.
Doug Yanega, senior museum scientist at U.C. Riverside's Department of Entomology, said he is skeptical that there are actually more roaches around this year than in the past.
Rather, he said, people may simply be seeing them more frequently, because they are particularly active on warm nights.
"They're making themselves a lot more obnoxiously visible," he said.
In Burbank, residents of one hillside neighborhood complained that big American cockroaches were climbing out of maintenance hole covers at night, said public works director Bonnie Teaford.
The city has instituted a program of regularly spraying around the maintenance holes, where from time to time the cockroaches are so thick that workers cannot see to do their jobs, she said.
“Any place you go in these nice, warm Mediterranean climates you have cockroaches,” Teaford said.