Saturday, July 4, 2009


The mosquitoes are ravenous!

I really have no idea how the Indians and the early settlers withstood the mosquitoes. I’m not sure that I could live in Minnesota without Bt or DEET.

I didn’t stock up on mosquito dunks this year – those cute little brown donuts of bacillus thuringiensis (Bt) that we usually float in all our sloughs and ponds. I didn’t even think about it until the first mosquitoes appeared about a week ago.

Now, I really regret that lapse in memory. Mosquitoes are always bad first thing in the morning and in the evening, especially after sunset. But this week, they swarm around me in full sunshine, at noon. Especially when I am hanging clothes on the line, both hands busy, face and arms completely exposed, or weeding the garden with my shirt riding up over my back and my ankles vulnerable below my jeans.

The mosquito dunks form of Bt is bacillus thuringiensis servovar israelensis. This bacterium attacks mosquitoes. It produces a toxin that inserts itself into the cell walls of mosquito larva guts, and lyses them, so the larva die. I love the idea of mosquito larva dieing from burst cell walls in their guts. It just seems so right. I also love that we can kill them with an environmentally friendly pesticide. The Bt has little or no effect on humans, wildlife, pollinators, or other beneficial insects.

But without the forethought of mosquito dunks, I am forced to rely on mosquito repellants. I’ve tried the nontoxic mosquito repellants – the citronella candles and the Skin So Soft lotion. They don’t touch Minnesota mosquitoes. Even the more suburban mosquito repellants don’t really work here. It takes substantial concentrations of DEET (N,N – diethyl – m – toluamide) to really repel mosquitoes. The nasty bugs are attracted to humans because of the odor of our skin and the carbon dioxide we breathe out. DEET jams the mosquitoes sensors so that they can’t land and bite successfully. We spray it in our hair, on our clothes, and rub it on our faces. It is such a relief to see the mosquitoes swarming around me, hear their incessant buzzing, and not be bitten.

My niece, Aubrey, asked what mosquitoes are good for. My gut reaction was “NOTHING!” But actually, we probably have so many barn swallows because of our mosquito population, and the beautiful gold and red bodied dragonflies swooping through our yard on iridescent wings eat many times their own weight in mosquitoes. In fact, the swallows nurturing babies in the rafters of the barn, and the dragonflies resting on flowers more than make up for the mosquitoes.

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