Invasion!

Although small and fuzzy, the forest tent caterpillar can become a real big problem–and the local Ministry of Natural Resources is expecting to see the insect menace rear its ugly head here very soon.
Back in October, the MNR conducted egg-band counts in 72 areas across Northwestern Ontario, with results indicating many areas in the region, including Fort Frances, likely will see high levels of defoliation and larva populations this summer as the insect enters the second year of its four year-cycle.
Although MNR forest health technician Mark Breon said there have been few reported sightings in town so far, one Fort Frances resident got a shock after first spotting the insects–which are distinguishable with its silky hair, blue stripe down its down and white keyhole marking on its back–on trees in her yard Sunday.
“There were masses of them. I was surprised at the quantity,” said Pam Munn, who lives on the 1200 block of Cornwall Avenue North.
When she saw the caterpillars had infested 11 of her chokecherry, apple, and flowering crab trees, she and husband, Terry, did all they could to stop the onslaught.
“We immediately sprayed them with Raid. It just instantly took care of them,” she remarked.
But getting rid of hundreds of caterpillars hasn’t been easy. “There are still clusters of them on the leaves and larger masses of them on the bark,” she noted.
And Munn has a feeling this is just the beginning. “We just hope we can reduce the damage done to our trees,” she said. “I’d like to make people aware they’re starting to hatch.
“Check your trees,” she warned.
While caterpillar attacks alone may not necessarily kill a tree, severe defoliation results in stunted tree growth. And when combined with additional stress (pollution, other insects, or drought), that could lead to mortality.
Preferred hosts are aspen, oak, apple, maple (except red maple), and birch. Mature caterpillars may move on to almost any plant species, including conifers, when they have consumed their normal hosts and are hungry.
Homeowners can treat their trees with a registered insecticide, or a homemade concoction such as soap and water. To prevent larvae from crawling up trees or other objects, a sticky substance, such as Tanglefoot, can be applied to a wide band of tape around the trunk.
Foil or plastic wrap should not be used as the first actually can cook the bark while the second can stunt the tree’s growth.
Egg-band count locations in the district, and the expected severity of infestation at that location, are as follows:
•north of Highway #11 at Flanders–light;
•about two km northeast of Pine Lake on Highway #11–light;
•1.2 km north on Highway #502–moderate;
•2.7 km west of Seine River crossing on Highway #11–moderate;
•12 km north of North Branch, off Highway #600 in Dewart Township–moderate;
•near the end of Highway #611 in Burriss Township–moderate;
•2 km north from Highway #11 on Highway #71–moderate;
•near Northwest Bay on Highway #613–severe;
•6 km east of Dearlock off Highway #600–severe;
•10 km northeast of Stratton in Chapple Township–severe; and
•2 km north of Barwick in Dobie Township–severe.
But Kenora looks to be getting the worst of it in the region, with 10 of 12 sites indicating “severe” infestation.
Of the 72 locations, 85 percent of those areas will suffer moderate to severe defoliation this year.
A total of 10,899 hectares of defoliation occurred in Northwestern Ontario since 1997. In 1998, the infestation expanded to 118,223 ha., and jumped to 1,481,124 last year.
At the peak of the last outbreak in 1991 in Ontario, the insects covered more than 18.8 million ha.
Forest tent caterpillar outbreaks have occurred in Ontario every 10-12 years since the first known outbreak in 1834. They should reach maturity in late June/early July, when they will seek sheltered places to form cocoons.
But that won’t be the end of them as they will emerge from these cocoons as moths about two weeks later, when they mate and then lay eggs around the twigs of trees.
The forest tent caterpillar population is expected to peak next year.