Cankerworms strip Durham trees naked

Sep. 07, 2013 @ 03:40 PM

Sara Davis Lachenman never thought her yard would look like Halloween in April, but that’s what happened this year.

Blame the cankerworm.

The pesky insects ate every leaf from her six willow oaks last spring at her Old North Durham home on Mangum Street, turning the property into a spooky place.

“They kept us inside our house for weeks, because when you walked outside, you got the cobwebs on you,” she said. “They essentially were chewing and pooping at the same time. You could hear this slight drizzle, all the time, when you were outside. So we hunkered down, and waited for it to be over.”

A two-week period in April was the worst time, when the cankerworms had essentially taken over her yard. It was like something out of a Stephen King movie.

“You could see the caterpillars everywhere – on the trees, on the house,” she said. “There were so many that they were climbing onto the house, thinking it was a tree and looking for foliage. There were millions of them – it was a colossal number in a very small area.”

At one point, Lachenman said, her mother went outside to pick up dead branches “and was trying to swat down all the cobwebs, and it was just this crazy, losing battle. Everything was shrouded in it. It looked creepy – like Halloween.”

But Lachenman is fighting back. She attended a Tuesday workshop at the Durham County Extension Service, and learned how to apply bands – similar to flypaper – on her trees this fall to prevent the problem next spring.

The sticky substance prevents female cankerworms from reaching the tree tops and laying eggs. It’s labor-intensive and expensive, but the gold standard for controlling the prolific insects.

Lachenman will begin the tedious process in early November.

“I felt like we were the epicenter of the outbreak in this neighborhood, and will do all I can to make our corner a little less of a horror movie,” she said.

Also working on the cankerworm problem is Alexander Johnson, Durham’s urban forestry manager.

Johnson said infestations in Durham have worsened in the past two years, and include areas around Northgate Park, Old North Durham, Trinity Park, Watts-Hillandale and Forest Hills.

Many of the trees there were planted in the 1920s through 1950s, and some are nearing the end of their lives. When cankerworms attack older trees, they can’t always bounce back like younger ones, “and it’s just another nail in their coffin,” Johnson said.

Johnson estimated that “thousands” of trees have been infected by cankerworms in Durham this year, and said the problem can only be managed.

“These insects are not imported – they are native to North America, and part of our natural ecosystem,” Johnson said. “Unfortunately, the urban forest is not a natural forest.”

“They don’t respect people’s property boundaries,” he said. “Banding can help reduce the population, but you’re not going to eliminate them.”

For questions about cankerworms, email Alex Johnson at