According to Jan Lundström, whose company Biologisk Myggkontroll combats mosquitos around the Dal River in central Sweden, this year is shaping up to be unusually bad.
“It’s about twice the normal amount of snow this year, and if this snow melts quickly and there’s a lot of flooding, it will produce an enormous amount of mosquitoes,” he said.
The floodwater mosquito, Ochlerotatus Sticticus, is much more aggressive than the more common snow pool mosquito, and can fly between 10km to 15km in search of victims.
When rivers flood much more than is usual, several generations of eggs hatch simultaneously, generating terrible swarms.
“If it’s really bad, you won’t be able to be outside at all,” Lundström told The Local. “People cannot cut the grass, they can’t pick berries. You cannot go out with your dog, because the dog will not lift its leg to pee, because if it does it gets so badly bitten.”
When the village of Österfärnebo, near Sandviken, was hit by floodwater mosquitoes in 2002, he remembers, it was like a ghost town.
“It was in August and it was absolutely deserted. You couldn’t see a person at all, and then suddenly I saw someone running out of a house, opening the door of their car, spraying everywhere and driving off.”
“You will get several thousand mosquitos in your car if you even open the door.”
Lundström said that his use of BTI, a bacteria which kills mosquitos, had now got the mosquito numbers in under control in Österfärnebo and other areas around the Dalälven river.
He said areas facing the biggest risk today were around other major rivers such as the Torneälven and Klarälven.
Many municipalities in Sweden are complaining that they are being given insufficient funds by the Swedish Board of Agriculture to battle the maddening summer pest.
Below is a sign erected in 2009 in Österfarnebo to warn drivers of the risk of sudden mosquito attacks.
“Drive Carefully. The Environmental Protection Agency has issued a warning about mosquitos,” it reads.
Lundström uses a helicopter to spray affected areas with BTI bacteria.