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A solution to summer pests: Annual spraying for tent caterpillars begins

Dealing with bugs at the lake often comes with the territory - but it doesn't have to.

For the past six years, the Little McDonald, Kerbs and Paul Lake Improvement District has sponsored an annual pesticide spraying, intended on killing off the ever-growing tent caterpillar infestation.

According to the University of Minnesota Extension, tent caterpillars are known for feeding off native Minnesotan trees, including ash trees, which are common on lakes in the Lake Improvement District.

Members of the Lake Improvement District voted to allocate funds collected through the organization's tax to the spraying of the bugs.

In order for the spraying to be effective, conditions need to be just right, said Lakes Improvement District Chairman Ardell Wiegandt. Pesticide needs to sit on leaves for up to eight hours, which means prime spraying time happens with there is no rain or excess wind in the forecast.

Spraying also has to happen when the tent caterpillars are a half inch in length.

"We have people around the lakes who look for them, and once they get over half an inch, they give me a call," Wiegandt said.

West Central Ag-Air out of Fergus Falls, Minn. does the spraying for the lake district. When the call is made and conditions are just right, it sends over airplanes, which circle the 130 acres of lake property.

Spraying typically takes place in the early morning hours, between 5 and 7 a.m., or evening hours around 8 p.m. Because planes fly relatively low to the ground to distribute the pesticide, Wiegandt said it's important people are aware it's going to happen before the big show.

The pesticide used by West Central Ag-Air is called Bacillus thuringiensis, commonly known as Bt. According to the business, Bt "only has effect on caterpillar species and has been in use for decades for caterpillar control throughout the United States and Canada."

According to Valent BioSciences Corporation, Bt is deadly to tent caterpillars when consumed - but not because the insecticide itself is toxic. Rather, it contains a protein crystal that, when mixed with the contents of the bug's digestive enzymes, proves to be fatal. The corporation also states the insecticide is not harmful to humans or the environment, as it stems from a naturally occurring bacterium.