Beijing Deploys Tiny Wasp Army Against Caterpillar Invasion

Beijing has unleashed an army of parasitic wasps against an invasive caterpillar infestation in the city. The fall webworm, a moth from North America that feeds on over 80 kinds of trees and crops, has been causing problems for residents. Nearly 700 million wasps have already been released this year to combat the pest.

The city's forestry protection center says warm winters have lifted survival rates for the moth, which overwinters as a pupa. The campaign includes hand-cutting silk nests out of trees and wrapping trunks in corrugated paper to trap descending larvae. Pheromone traps and light traps are also being used.

The wasps attack the pupal stage, laying their eggs inside the moth's cocoon and emerging as a new generation. Officials say the moths can skeletonize a tree until only the veins remain in bad years. Residents are advised to keep their distance from the caterpillars, but they pose no toxin or disease risk.

The forestry protection center told Beijing Daily that successive warm winters have led to this year's peak infestation. The city has begun injecting micro-doses of insecticide through drill holes for tall plane trees, an effect that lasts four months.