Ponoka County advises of outbreak of Forest Tent Caterpillars

PONOKA COUNTY -- An outbreak of Forest tent caterpillars has been observed across Ponoka County.

This is according to the County's Agriculture Service Board, which says the tiny insects have been observed in large numbers in various parts of the municipality. Though small in size and stature, Forest tent caterpillars can cause immense damage to local trees and forests by way of defoliation.

The Ponoka ASB says that while most healthy trees can survive one or two years of defoliation, repeated attacks can weaken them, making them more vulnerable to disease, drought, and other pests. It's noted that they are particularly attracted to the Sugar Maple Aspen Oak Birch, and that in heavily infested areas, residents may notice temporary tree thinning or browning due to leaf loss.

Forest tent caterpillars are native to North America and are a common defoliator of hardwood trees. Despite their name, they don't build tents like other tent caterpillars. Instead, they spin silk trails on tree bark and branches, to help guide them between feeding and resting areas. These caterpillars are about two inches long when fully grown, and are easy to recognize by their blue and black bodies.

If you notice a large amount of these tiny critters on your trees, you can take several steps to address this. The first recommendation is to scrape off egg masses or clusters of caterpillars in smaller areas, while another tip is to use Bacillus thuringiensis (Bt), a natural bacterium that targets caterpillars but is safe for other wildlife. If the situation is severe or persistent, residents are asked to consult with a local arborist, or the County Office.

Forest tent caterpillars typically emerge in the spring, as larvae feed heavily on tree leaves for about five to six weeks before pupating.