Rain, warmth creating perfect storm for mosquitoes

Mosquitoes, like the rest of us, are still waiting for summer to arrive.

All the recent rain normally would be ideal for the pests, but unseasonably chilly temperatures have cooled their romantic desires and conspired to keep their populations down.

"The cooler temperatures are suppressing biting activity," said Mike Szyska, director of the Northwest Mosquito Abatement District that serves communities in Northwest Cook County.

That likely will change, though, because as temperatures have risen so will the swarms of skeeters that thrive in warmer temperatures. And because there is so much excess water this year, there are more places for mosquitoes to lay their eggs.

Weather forecasters say temperatures are expected to start climbing in time for the start of summer, which could launch a biting bug boom. While the anticipated showers may keep West Nile-carrying culex mosquitoes at bay for the time being, floodwater mosquitoes will bask in the wet warmth.

"Every year is different because the weather fluctuates so much," said George Balis, an entomologist for Clarke Mosquito Control based in Roselle. "In the short-term we are forecasting a large increase in floodwater mosquitoes, though, and we're anticipating a lesser number of culex mosquitoes."

The constant rain does help wash some mosquito eggs away, though experts note they can remain viable in dry locales for seven years.

"With all the rain we're having, all that's missing at this point is the higher heat and as soon as that kicks in, then we'll see a tremendous increase in activity," said Tim Martin, co-owner of JT Skeeter Beater in Vernon Hills.

According to figures from the National Weather Service offices in Romeoville, the Chicago area has had 13.53 inches of precipitation since March 20, the 20th-wettest spring through Tuesday. But more showers are forecast until the official first day of summer on Sunday, which could move this year further up the charts.

Last year's springtime precipitation totals came in at 11.9 inches. The wettest spring on record occurred in 1983 with 17.71 inches of rain.

Excess rain helps mosquito populations because they find places that normally don't get wet or places that usually dry out before summer begins.

Balis said Clarke crews have been busy this spring.

"We're out more and treatments have been more plentiful because there are more places that need to be treated because of the rain," he said. "We haven't seen a dramatic difference in the need to treat in stalled developments or at foreclosed homes. We haven't seen a lot of abandoned lots or houses anywhere."

Trees also have benefitted from the rain, sprouting magnificently colored flowers and dropping a barrage of seeds. Unfortunately, much of that eventually winds up in street gutters and can clog storm drains. The clogs can become nests for mosquitoes.

Naperville Public Works Director Dave Van Vooren said his crews have stepped up efforts to make sure the drains flow properly.

"The maple trees with those helicopter things they drop are the worst and we've watched the areas where they're at to make sure water has a chance to wash away," he said. "There's no doubt late April and May were exceedingly wet and we were a little busier, but it's nothing that will have a significant impact on our operational budget."

Mosquitoes are fought on almost every front during the summer, except in the area's forest preserves.

"Mosquitoes are one of the seasonal challenges," said Kane County Forest Preserve Nature Programs Manager Valerie Blaine. "In the big scheme of things they're just part of Illinois summer and some years are more challenging than others."

Blaine said she can only recall one outdoor program that ever had to be moved because of mosquitoes; otherwise she just recommends people wear pants and long-sleeves if the bugs are really bad.

That's similar to the advice DuPage County Health Department officials are giving in the wake of this year's first positive test in Lisle for West Nile-carrying culex mosquitoes. The positive test came later this season than in previous years, which is good news for humans. The longer it stays cool and wet, the better chance humans have to avoid infection since culex mosquitoes like it hot and dry.

"The longer we go without having that first hatch, the longer it's going to be before we have a population explosion," said University of Illinois Extension Green Industry Programming Coordinator Richard Hentschel.

But West Nile-carrying mosquitoes are inevitable.

"The one thing about West Nile is once it's in an area, it's here to stay," said DuPage Health Department spokesman David Hass. "Wear the longer clothes if you're out between dusk and dawn, use a repellent and if there's standing water lying about, refresh it or dump it out. Stagnant water is where the culex mosquito breeds. We always tell people not to curtail their activities, just be cautious."