09/22/2026
These creepy-looking webs aren’t made by spiders. 🐛🕸️ They’re built by fall webworm caterpillars (Hyphantria cunea), a species native to North America. The caterpillars live and feed together inside large silk webs that can cover the ends of entire branches. As they grow, they expand the web to reach more leaves.
Fall webworms feed on many kinds of deciduous trees, including cherry, birch, walnut, maple and willow. Their nests can look dramatic, but in Ontario the damage is usually limited because most feeding happens late in the growing season, after the tree has already produced much of its energy for the year.
By September, the caterpillars leave the web, drop toward the ground and pupate in leaf litter or soil. They spend the winter there before emerging later as moths. In Canada, fall webworms typically have just one generation each year.
Nature can look a little strange when you stop and look closely.