Widespread damage in rural areas can be seen to poplar trees due to tent caterpillar infestations.
The caterpillar got its name because it builds tent-like structures in trees.
Tent caterpillars feed almost exclusively on deciduous trees, including aspen trees, ash, fruit trees, maple, oak, birch, elm; they also rarely nibble on other garden vegetation such as strawberry leaves.
“There are tent caterpillar outbreaks about every 15 years and they last about three years,” says the Winnipeg public works website, “The mature larvae are 45-55 mm long and are bluish brown in colour with diamond-shaped white spots on the middle of the back of each segment. It has two thin, prominent broken yellow lines that extend along each side of its hairy body.”
John Gavloski, Entomologist of Farm Production Extension, for Manitoba Agriculture says, “The tent caterpillars aren’t a serious threat to farmers, because they usually don’t feed on crops.” He adds, “The caterpillar begins pupating in mid to late June, and are then they are done for the year.”
Tent caterpillar’s damage is mostly aesthetic. Healthy trees will not endure permanent damage, and trees will leaf out again in the same season.
“The infestations this year are higher than average, but are in localized hot-spots, and not widespread”, says Gavloski. He adds that Manitoba Agriculture discourages public from general spraying, especially on flowering trees, which can hurt wildlife and helpful insects.
Products such as Btk and Dipel are bacterial sprays recommended to control infestations. These sprays kill tent caterpillars, but are safe to birds and other insects.
Last week in the Assiniboine Valley, the highway was darkened where caterpillars had crossed.
