BRIPORT — Abundant rainfall coupled with late-summer heat and humidity have contributed to one of the worst mosquito outbreaks ever, though cooling temperatures this week should soon take some of the sting out of the latest adult hatch, local insect-control officials said.
“Things have gone south; it’s not good right now,” Paul Doty, manager of the Brandon-Leicester-Salisbury-Goshen (BLSG) Insect Control District, said late last week. He noted a recent spike in the mosquito population — particularly in the Lake Dunmore region.
That recent spike in part stemmed from the difficulty in pinpointing, from the air, specific drop zones for larvicide that has been applied by officials in an airplane owned and operated by the Lemon Fair Insect Control District (LFICD), which includes the towns of Bridport and Cornwall. The airplane this year dropped mosquito larvicide on an estimated 9,500 acres in the BLSG and LFICD districts, as well as in the town of Weybridge, which is its own, independent insect control district.
Tom Baskett, chairman of the LFICD, said the 9,500 acres treated this year is up roughly 2,500 acres from last year. The LFICD airplane made around 60 sorties this year, compared to 47 all of last year, according to Baskett.
While the larvicide drops in general provided great relief to district residents, officials acknowledged that the substance was harder than usual to direct this year due to denser-than-usual vegetation in floodplain areas. Weather conditions also meant farmers were unable to clear cropland as regularly as usual, thereby resulting in more cover for the standing pools of water in which mosquitoes could lay their eggs.
“It’s difficult to see (small pools of) water when you’re going 100 miles per hour,” Baskett said of the challenges of aerial larvicide drops.
As a result, August has been more buggy than earlier this summer, resulting in around 40 requests per day for spraying of chemicals to kill adult mosquitoes in the BLSG district, according to Doty.
“We have four trucks on the road every evening,” Doty said of efforts to keep pace with demand. “But with that kind of an area, it will take some time to control. People need to be patient with us; it’s just going to take a while.”
But Doty stressed things could have been a lot worse — particularly considering the Brandon area has recorded 11 inches of rainfall since June.
“The summer as a whole has been pretty successful, as far as keeping (mosquitoes) in check,” Doty said.
Evening temperatures were forecast to dive into the 40s this Thursday and Friday. Such temperatures tend to limit adult mosquitoes’ movement, according to Alan Graham, vector management specialist with the Vermont Agency of Agriculture. The first couple of frosts should knock out the mosquito population, he said, but there remains potential for more mosquito hatches this year if the region gets another dose of two-or-more inches of rain coupled with high temperatures.
“An egg can (mature) into an adult in five days in warm weather,” Graham said.
Thankfully, state funds have proved adequate to cover the larvicide purchases, which are bankrolled through a tax on motorboat registrations. That annual pot of money was supplemented by a special legislative appropriation a few years ago. Towns in the mosquito control districts also kick in money at their annual town meetings.
State Entomologist Jon Turmel stressed that while around $100,000 remains for larvicide purchases into next year, those resources would probably not be adequate to cover as active a mosquito as this year.