An unseasonably warm March does not necessarily mean area residents will see more mosquitoes, ticks and other pests, but they may appear earlier, if trends continue.
Greg Inman, director of the Boone County Health Department’s Environmental Division, said state health officials “don’t anticipate a major increase” in the number of mosquitoes or ticks following the fourth-mildest winter in Indiana’s history, and a March that broke or tied 7,000 high-temperature records nationwide.
“They may come out a little sooner,” Inman said. “The main source will be if we have warm weather associated with any time of rain event.”
That combination could occur; the National Oceanic and Atmospheric Administration, a branch of the National Weather Service, said on Thursday, March 15, that there is a 33 percent chance Indiana will experience warmer than average temperatures through late June.
The southern two-thirds of Indiana are also at an above-normal risk of spring flooding. “Soil moisture and river levels” were above average on March 15, NOAA said. “Odds favor above-average April rainfall for the Ohio River basin,” the agency said.
Winter temperatures in Boone County averaged about four degrees above normal, NOAA said.
“Without a real hard freeze, you run that risk of not having a large kill of the insects,” Inman said. “A lot of the ones (infected) with West Nile virus will over-winter as adults; they’re just hanging out in warm areas.” Mosquitoes associated with West Nile virus, however, emerge at the end of summer, when it is typically drier, he said.
Some mosquitoes remain in the egg stage over the winter, Inman said. “We may see some of those come out sooner than we normally would,” he said.
Recent cool weather will slow the emergence of mosquitoes, he said, “than if it had stayed hot, as it was in the beginning of March.”