Even though it’s that time of year when we’d normally be banding our trees to reduce the spread of cankerworm – a kind of caterpillar that feasts on leaves in the spring – some recent good news has changed that! Earlier this fall, local arborists and researchers have determined that Charlotte’s cankerworm population has seen a significant decline, meaning that you do NOT have to band your tree this season. In fact, we recommend removing any remaining bands from your trees because their sticky substance can trap unintended insects. Bands on street trees should remain.
So, what happened to the cankerworm? Local arborists suspect some late frosts in the last few years have killed off many of the newly hatched caterpillars. These spring frosts, combined with diligent tree banding from caring Charlotteans, decreased the number of cankerworms in our city remarkably. Data shows that in spring of 2016, the city of Charlotte tracked 38,948 cankerworms in 163 locations. By spring of 2020, the cankerworm count was down to 117 individuals.
For those unfamiliar with the cankerworm, these critters emerge from their silk cocoons in the soil around late fall and begin to mate. Soon after, the winged male moths fly away and the wingless females migrate up our largest trees to lay their fertilized eggs in the canopy. The eggs overwinter amongst the branches, and by spring, the baby cankerworm caterpillars hatch and mow through the leaves. Some years the population was so large you could actually hear the munching! To stop the migration, city arborists and homeowners would wrap the trunks of largest of trees – mostly our oaks – with plastic and coat them with a sticky substance to stop the female cankerworm in her tracks.
While it’s good news that we can stop wrapping, we should remain vigilant. Cankerworms are a native insect, so they will never go away completely (which is a good thing, since they do serve a role in our ecosystem as food for birds and other wildlife). Report any spotted cankerworms to the city of Charlotte’s “Great Cankerworm Count” to help them track population numbers. City officials will still be monitoring street willow oaks and keeping a close eye on the situation. 🛑🐛
More info found about cankerworm banding and tracking in the link below: