Though they are not out in full force yet, Forest Tent Caterpillars are once again on the move.

The influx of tent caterpillars over the last few years is being attributed to an outbreak in populations. Outbreaks can last from three to six years and typically come to an end when disease wipes the caterpillars out. Many places in Saskatchewan are believed to be in their fourth year of an outbreak.

Tent caterpillars can be harmful because they eat the leaves off of trees, though a healthy tree is generally able to grow back their leaves after the caterpillars have had their fill.

For those interested in other ways to fight off an outbreak there are products available that aren't harmful to humans or pets. A product known as bacillus thuringensis kurstaki (BTK) is recommended.

BTK is specific to caterpillars with no environmental or health effects on people, animals, pets or even other insects. While effective, the spray has been difficult for stores to stock due to its popularity.

If you cannot reach the tops of trees, however, applying the product in portions from the ground will likely not gain you anything.

On smaller trees, simply put on a pair of old gloves and strip the caterpillars out of the tree. The best time to catch them is early morning or into the evening as they tend to congregate in bunches or groups.

Tent caterpillars usually attack deciduous trees and the Ministry of Agriculture believes that because caterpillars are a forestry pest, they will not be a concern for farmers.