Cankerworms are back, munching on Charlotte’s tree canopy

A cankerworm munches on a Bradford pear tree leaf in west Charlotte in April 2015.
A cankerworm munches on a Bradford pear tree leaf in west Charlotte in April 2015. tsumlin@charlotteobserver.com

Cankerworms have begun to hatch, slink and munch on Charlotte’s tree canopy again.

The little green caterpillars typically emerge this time of the year from eggs laid by their wingless moth mamas in December.

Cankerworms have been confirmed in some areas of Charlotte for at least a week to a week and a half, city arborist Tim Porter said.

While cankerworms in most cases don’t kill trees, repeated defoliation can weaken trees, making them more vulnerable to age, drought, other insects and disease. They appear from Georgia to Nova Scotia and west to Texas, and Charlotte has seen severe infestations of the worms.

The city conducts a tree banding grant program, working with community groups and a street tree banding program each fall and winter, Porter said.

Homeowners apply a band of paper-like material around their trees and add a coat of sticky material to prevent cankerworm moths from crawling up the trees to lay their eggs.

“The tree banding efforts can greatly reduce the nuisance and environmental impact the cankerworm caterpillars have when they emerge in the spring,” Porter said.

Despite efforts to reduce their presence, however, Charlotte’s cankerworm population has refused to let up for 30 years.

Entomologists are stumped as to why the population continues to grow, but the city’s large number of old willow oaks could promote the annual infestation, city officials said.

Joe Marusak: 704-358-5067, @jmarusak