What’s Up With The Bands on Campus Trees?

Perhaps you’ve seen them — you know, those campus trees with six-inch bands wrapped around the trunk. And you may have wondered whether that banding is the product of a crazy prank or part of some signage that someone forgot to remove.

Turns out, these odd-looking bands are actually designed to save some of the most vulnerable campus trees from one of their most hostile enemies — the itty, bitty cankerworm. At about an inch, you wouldn’t think the cankerworm could harm a big maple or willow oak tree, but these small but mighty pests can infest a tree, compromising the tree’s health and leading to defoliation (read why that’s a problem).

The impact of cankerworms near campus is clearly seen in this defoliated tree on the right as compared to a healthy tree. Photo courtesy of Stephen Barilovits.

“Cankerworms have become more and more abundant,” said Dr. Steve Frank, an NC State associate professor of entomology and an N.C. Cooperative Extension specialist. “In Raleigh it’s getting worse and worse.”

So what can be done to stop these worms from wreaking havoc? You guessed it: sticky bands.

The bands limit the spread of cankerworms by disrupting their life cycle. Eggs hatch in early spring and the worms spend the summer cocooned on the ground under trees. They emerge in the fall and winter and begin the upward journey into tree branches where they lay eggs before dying. Sticky bands trap female moths, who are wingless, as they climb the tree’s trunk. Fewer eggs, of course, mean fewer cankerworms.

In September 2014, a small army of volunteers from NC State’s Parents and Families Weekend canvassed campus to apply the first step of the banding to about 80 campus trees. They wrapped strips of poly fill material around tree trunks and stapled over the batting with roofing paper. The batting conforms to the tree, preventing savvy moths from bypassing the band through nooks and crannies in the tree’s bark.

Later in the fall, the second step will be completed: slathering Tanglefoot, a sticky paste of natural resins, oil and wax, to the band. As the name implies, this is what stops the cankerworm in its tracks. Last year Frank’s students counted up to 1,000 trapped moths per tree per week. Pretty impressive, right?

So next time you’re on campus and notice a tree wrapped with a band of sticky sludge, know that tree has a lot to gain from this odd-looking, but effective solution.

Learn more about the cankerworm at Dr. Steve Frank’s website

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