The population of tent caterpillars on the Sunshine Coast “will probably dramatically increase over the next couple of years,” warned retired agrologist Gus Butt.

“There have been sightings from Gibsons to Halfmoon Bay and probably further along the Coast,” he said. “The area that is currently the hardest hit is in the Langdale area, where the alders along the highway are almost completely defoliated.”

According to Butt, tent caterpillar populations experience a “boom to bust” cycle.

The insects hatch annually, but only once, with populations ranging from very low to very high.

Their numbers have been tied to a polyhedron virus, the agrologist said, highlighting a possible cause for their fluctuating numbers year to year.

Tent caterpillars tend to favour aspen, poplar, alder and fruit trees, he said, and the new larvae are responsible for constructing the web-like tents seen straddling the nodes of Coastal trees.

Those tents, if accessible, can be cut from the tree and disposed in a sealed garbage bag, Butt advised. Chemical products in the form of tree sprays are also effective.

Butt said that throughout his career, he has experienced two explosions in the populations of tent caterpillars, including one episode on the Sunshine Coast just under a decade ago.

He said the population will likely continue to increase in the coming years, until the insects’ numbers once again dwindle due to the virus.