By DAVID BORAKS
“Hey, what is the deal with all of the little green worms falling from above?” Davidson resident Sara Rubens asks.
They’re canker worms, and depending on whom you ask they’re either cute pets, or awful pests. The eggs hatch and worms begin dangling every year as the foliage begins to appear, which this year seems to be a bit earlier than usual.
Davidson College biologist Chris Paradise says two species of canker worms appear around here: The ones we’re seeing right now are offspring of the fall canker worm, and are in the Geometridae Family of inchworms or loopers.
The caterpillars actually can be a major problem, causing defoliation and stress. “That could weaken trees and allow other environmental factors, such as insects and pathogens to successfully infest,” Professor Paradise said Tuesday.
Steve Frank, of North Carolina State University’s Entomology Department, wrote about the worms the other day, saying they “seem to be super abundant this year.” But he doesn’t think they’ll be a major threat. And he notes that the caterpillars will provide a nice food supply for songbirds.
That may be true, but, our colleague Lyndsay says, “they’re not eating them fast enough.”
Putting sticky bands around tree trunks in the fall can help prevent adult females from climbing up trees to lay eggs on branches, Prof. Paradise said. However, he added, banding in the spring may be important if we have both species of canker worm in the area.
And here’s an interesting tidbit: the females of both species become wingless moths. (Take a look at one here. Ugh.) Banding can keep these wingless females from crawling up into the trees.
2014 update – April 17, 2014, DavidsonNews.net, “Green worms are back, and now they’re being studied.” – a 2014 followup interview with Prof. Chris Paradise about cankerworms and banding.
City of Charlotte canker worm information page
March 23, 2012, Steve Frank, N.C. State University, blog article on canker worms.
Recipe for N.C. Canker Worm Sorbet.