They're back. By June 14, localized defoliation caused by the forest tent caterpillars had been observed in the Bathurst, Woodstock and Mactaquac areas of New Brunswick.
Tent caterpillars are commonly referred to as armyworms because they congregate in large numbers. The species is native to the province and is one of most widespread defoliators of deciduous trees in Canada. Outbreaks occur every 10 to 12 years, with the last outbreaks in New Brunswick recorded from 1979 to 1984 and 1991 to 1996.
It is at the caterpillar stage when the pest feeds on the leaves of aspen and other hardwoods. Populations are controlled by predators, parasites and disease. These controls in nature have already been at work within localized areas, and there are no plans to conduct any spray program.
Caterpillars will soon complete their feeding and will form yellowish-white cocoons in which they will transform into adult moths.
Property owners within these areas can take a number of steps to reduce damage:
• keep defoliated or damaged trees well watered to prevent any additional stress - defoliated trees will typically produce another crop of leaves in the same year;
• turn off outdoor lights around your home. Adult moths are night flyers and are attracted to lights, so trees in well-lit areas will typically have more eggs laid on them;
• in the fall after leaves have fallen, check small hardwoods for the presence of caterpillar egg bands laid on branch twigs in tree crowns. If possible, these should be removed manually;
• to prevent caterpillars from migrating into trees from which egg bands have been removed, apply a pest barrier product such as tanglefoot on the trunk in the spring after leaves flush; and
• there are also a number of insecticides registered for use against this pest to help control the caterpillar stage.
