It happens every year. Your garden is looking great and then you see big ugly webs in your trees and shrubs. Inside the webs are colonies of caterpillars (Webworms) munching the leaves off your trees. Before panicking, the first thing you should know is that these webworms don't typically cause a lot of damage to trees and shrubs. They look far worse than they are. So the most organic approach is to simply let them be. Even if they defoliate your tree, it's usually late enough in the season that it doesn't harm your tree.

It is apparent all throughout the valley that the Fall Webworm is in full swing of its life cycle (in the Okanagan they get active March-May). Webworm populations normally rise and fall from year to year and it seems that populations are peaking this year. Even though the nests/webs in the trees are quite unsightly, they do not usually do permanent damage to mature trees.

They are a part of nature and are common to this area. The City of Kelowna, Central Okanagan Regional District and the District of Lake Country do not apply pesticides in public spaces or on private properties to control this pest. They are mostly an esthetic problem and not a threat to their host.

Webworms are the caterpillar form of a small white moth. The moths lay their eggs on the underside of leaves in the early summer. Once the larvae hatch they spin webs for protection and then feed for about six weeks on the leaves of the host tree or shrub they are on that is when they look the worst. They can eat all the leaves on a branch, but next spring new leaves will emerge. Over the course of the winter months the webbing will deteriorate and disappear.

Spraying chemicals to try to control this pest is not very effective and can be harmful to beneficial insects in the surrounding areas including butterflies. The nest (webs) can be pruned out and then submerged into warm soapy water, then bagged and put into the garbage-- not the green recycling bin as this can contribute to the spread of the pest. Pruning can alter the form of the tree or shrub leaving a less than desirable plant specimen. Birds and wasps are natural predators to this pest.

If you have a tree or shrub on your property that is infested with the Webworm you can make a hole in their nest (web) either by spraying water or creating a hole with a stick to open up their habitat so the natural predators are able to go in and feast. This is the best solution. Plan to encourage beneficial insects next year by planting sunflowers or other plants in the daisy family in your yard.

The Webworm is often confused with the more destructive Tent Caterpillar. Fall webworm larvae are found in nests that enclose foliage. Webworm nests (webs) are out on the ends of the branches, enclose foliage and can grow to 3 feet in diameter, with the caterpillars inside the nest. Tent Caterpillars generally are closer to the trunk of the tree or shrub, usually in the crotch or fork where the branch and the trunk meet, and the larvae are found on the surface of the tents.