Creepy crawlers are causing conundrums in Armstrong.

Since 2014, the city has seen an increase in western tent caterpillar and fall webworm infestations.

Staff has been receiving numerous inquiries on the eradication and prevention of their nests. Both insects typically hatch once a year.

“These insects have similar properties to one another and can be dealt with in the same fashion without needing to identify which is which,” wrote deputy corporate officer Natalie Garbay in a report to council.

Tent caterpillars and webworms are native to Canada and the U.S. and, typically, their infestations last between two-to-three years and happen again every seven-to-10 years, though the range has fluctuated with changing weather patterns, geographic location and the availability of host trees.

The caterpillars often construct tents in host trees such as willow, apple, plum, cherry and oak. The worms seek out alder, ash, choke-cherry, cottonwood, walnut, willow and fruit trees.

“Tent caterpillars tend to devastate the integrity of their host trees, rendering them susceptible to cold, disease and drought,” said Garbay. “Webworms rarely cause permanent harm to their host trees.”

Natural enemies for both insects include bats, birds, parasitic wasps and small mammals.

Based on information provided by local nurseries and Canadian government recommended websites, the city has posted nine options on its website – – for residents to control and reduce infestations on their properties.

Spraying has not been investigated as an option due to the limitations of spraying near water courses, and the negative impact sprays can have on the beneficial insects the trees and flora need.

Council voted unanimously to have staff research the problem and bring back proposals for the 2016 budget deliberations.