Rain brings mosquitoes

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(Host) State officials say this year’s wet weather has resulted in a bumper crop of mosquitoes. But nothing compares to the infestation that occurred in several Vermont towns in July of 1989. VPR’s Steve Zind reports.

(Zind) Not everyone welcomes the cool relief that comes with a heavy downpour on a hot summer day. A heavy rain can push the waters of the Otter Creek over their banks and into more than twenty thousand acres of low lying land, creating a huge mosquito nursery.

When the adults emerge from the water, the winds gather them up and deliver them to Brandon, Leicester, Salisbury and Goshen. Fifteen years ago an especially wet spring and summer brought the towns clouds of mosquitoes and unwelcome national headlines. With Vermont’s image at stake then-Governor Madeline Kunin requested emergency funding to combat the insects.

(Jon Turmel) “It was miserable. If you drove around, it looked like a deserted town because nobody was going outside.”

(Zind) Jon Turmel is Vermont state entomologist. Turmel says since the 1989 infestation, the state and the affected towns have maintained a program designed to keep mosquitoes at bay. Every spring they use a larvaecide to kill newly hatched mosquitoes in the water – then they follow up by spraying to kill adults.

The larvaecide is non-chemical. The spray used to kill the adult mosquitoes is part of a chemical family known as pyrethroids.

Ben Davis of the Vermont Public Interest Group says the use of pyrethroids is both ineffective and dangerous.

(Davis) “I’ve seen studies show that over 99 percent of the spray has no effect on the target pest. There’s also a human health component to this. They’re nerve poisons.”

(Zind) Davis says pyrethroids are also a common ingredient in insect foggers sold in stores. Jon Turmel says only a small amount of pyrethroids is used in the mosquito control program. He says the program has been very effective in preventing outbreaks like the one in 1989.

(Turmel) “In the past I used to do a lot of biting counts. Stand there for a one-minute period and count how many land on you. [In] previous years, some areas would have biting counts of 150 to 200, that was in the Brandon areas. Now that we do controls it’s far less.”

(Zind) Turmel says that once again wet weather has created favorable conditions for mosquitoes.

(Turmel) “We’ve been getting calls from areas that normally don’t have mosquito problems.”

(Zind) Turmel says despite the above average number of mosquitoes, it’s nothing compared to the summer of 1989. He says the state has no plans to spray in other areas this summer.

This spring, for the first time the state used the non-chemical larvacide around the state park in North Hero. Turmel says that program is likely to continue in future years.

For Vermont Public Radio, I’m Steve Zind.

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