31/05/2026
Forest tent caterpillars have been identified in the County of Wetaskiwin. Forest tent caterpillars are a serious pest that effect many species of deciduous trees in North America. When outbreaks occur, they cover extensive areas and can completely defoliate host trees. Eggs hatch and larvae begin feeding on newly emerging leaves in late April to early May.
Prevention and Management
Pest management strategies vary depending on several factors, including:
▪ the population level of the pest,
▪ the expected damage of the pest's activity and population level,
▪ how many individual host specimens are affected,
▪ the value of the host(s) versus the cost of pest management.
Potential strategies include:
▪ removing colonies of young larvae by hand or with pressurized water, applying a registered insecticide against larvae for larger trees or in forested situations.
▪ Search Health Canada’s Pesticide Product Information Database for currently registered pesticides and product information for use against forest tent caterpillars. Apply registered products only as necessary and follow all directions and precautions noted on the manufacturer's label: https://pest-control.canada.ca/pesticide-registry/en/disclaimer-page.html
Rental Equipment
The County of Wetaskiwin offers a "bug sprayer" for rent that can be used to spray your trees. This self-contained trailer sprayer unit can spray trees up to 40 feet tall. It has its own motor and handgun nozzle to spray trees. It requires a 2 and 5/16” ball to pull the trailer and can be rented for $20.00 per day or $40.00 for the weekend. Click here for more information on rental equipment: https://www.county.wetaskiwin.ab.ca/175/Rental-Equipment
For more information about forest tent caterpillars, visit https://www.county.wetaskiwin.ab.ca/212/Forest-Tent-Caterpillars. For further questions or clarification, please contact Stefanie de Boer, Horticulturalist, at 780-351-3321 ext. 2271.
