CHICAGO (WBBM NEWSRADIO) — A rainy spring has some pest control companies warning Chicago could be headed for a rough mosquito summer, but local experts say it is still too early to know exactly how bad things could get. Chicago recently ranked second on Orkin’s annual list of the country’s worst cities for mosquitoes, behind only Los Angeles. Terminix also recently labeled Chicago a mosquito “hot spot” after a wetter-than-normal spring.
But Mark Clifton, executive director of the North Shore Mosquito Abatement District in Northfield, said mosquito activity depends on more than just rainfall. “I think in April we did have an early kind of aggressive start to the season,” Clifton told WBBM Newsradio. “But since then, it’s dried down and the leaves are out on the trees and they soak up a lot of water.”
Clifton said heavy rain can create mosquito outbreaks, but weather later in the summer often matters more than spring rainfall alone. “If it’s cool out, they’ll be kind of passive and subdued,” he said. “Once it becomes warm, I think there’ll be a lot more aggressive and seeking blood and harassing people.” Mosquito experts say standing water, not just rain itself, is one of the biggest drivers of mosquito activity. Clifton said mosquitoes commonly breed in buckets, flowerpots, clogged gutters, bird baths and children’s toys left outside. “Any sort of depression in a yard or really anywhere that rainwater collects for more than a handful of days can make mosquitoes,” Clifton said. He said if standing water remains for about five days, mosquitoes are likely to appear shortly afterward.
Mosquito abatement districts across the Chicago area are also ramping up trapping and testing programs as warmer weather approaches. The Chicago area is also seeing more invasive mosquito species than in past decades, according to Clifton. He said one invasive species becoming more common is the Asian tiger mosquito, originally from Asia, which is known for aggressive daytime biting and breeding in containers around homes. “It’s here and it’s a pretty aggressive biter,” Clifton said, adding that the bigger long-term trend is that mosquito season itself is expanding. “We used to have maybe a four-month mosquito season,” Clifton said. “And I think now it’s safe to say it goes from April to October.”
Clifton said mosquito pools carrying West Nile virus have already tested positive in Cook County. “Maybe in mid-July is where we really expect to see a high amount of West Nile virus and a real risk to humans,” he said. According to the Illinois Department of Public Health, West Nile virus is the most commonly reported mosquito-borne illness in Illinois. Symptoms can range from fever and headaches to severe neurological illness in rare cases. Clifton said homeowners can help reduce mosquito activity by eliminating standing water around their property, using insect repellents and wearing protective clothing outdoors. He added that even a strong fan can help because mosquitoes are weak fliers.
Cooler temperatures have helped keep activity subdued for now, despite recent rainfall.
Cooler temperatures have helped keep activity subdued for now, despite recent rainfall.
