BC spongy moth traps target invasive pest before it spreads

The Canadian Food Inspection Agency is conducting surveillance for the spongy moth, an invasive pest that devours leaves and can completely defoliate trees across B.C.

Cardboard boxes hanging high in tree canopies in Tsawwassen mark the front lines of this environmental defence. Since the 1990s, the CFIA has run routine annual surveys using pheromone traps to monitor uninfested areas. The lures are targeted and safe—harmless to humans, pets, birds, and other insects like bees and butterflies. Traps are hung high in the tree canopy, out of reach of day-to-day activity.

Spongy moths have already been detected in British Columbia, and eradication efforts are underway. Over 300 known host species are at risk. B.C.'s coniferous softwoods are mostly safe, but broadleaf and ornamental trees are on the menu: Garry oak, arbutus, red alder, aspen, cottonwood, maple, orchard fruit trees, nut trees, and many urban ornamental species would be severely impacted.

When traps catch a specimen, genetic testing at a CFIA lab determines the species. If fall survey data shows a rising population, an expert technical committee will recommend a response that could trigger localized spraying by the municipality and province.

Alberta, Saskatchewan, and Manitoba have already successfully detected and eradicated the pest. Ontario, Quebec, New Brunswick, Nova Scotia, and PEI have not. If the moth gains a stronger foothold in B.C., regulated quarantine areas could restrict movement of nursery plants, Christmas trees, patio furniture, and vehicles—all requiring inspection certificates before transport. The CFIA advises the public to inspect gear like RVs, trailers, and camping equipment for moths or egg masses before moving them, and to report any sightings immediately.