Tent Caterpillars

Just some thoughts on the Tent caterpillars that are migrating from their nests…We’ve been heading into the upswing of their 7 to 9 (or so) year cycle. It’s amazing how many there can be. Some of us who have lived here a long time have been able to observe these cycles. Remember 1985? Cars were skidding on the streets because of the thickness of their bodies.

I think it helps to know some fun facts about our creepy crawly relatives and the meaningful place they hold in the bio-system. Their host plant is the Red Alder (called “red” because of how they look in the spring when the buds are swelling.) In the years when the Tent caterpillars’ numbers are large, they all but completely defoliate the alders. This opens up the forest floor to sun, rain and air circulation.

The fallen insect frass, aka caterpillar poop, provides rich nutrient to the baby conifer seedlings and saplings. When you hear the raining sound of something that isn’t rain, know that it is just Mama Nature fertilizing her garden. During this time the conifers enjoy a huge growth spurt and are able to get a boost past the understory brush. The Alder trees have the role of preparing the ground for the royalty of the great coniferous forest, primarily Douglas Fir, Western Red Cedar and Western Hemlock. They take nitrogen out of the air and deposit it into the soil (magic, right?) If you pull a baby Alder seedling from the ground and look at the roots, you can see the little nitrogen nodules.

When the caterpillars leave their nests, they eat and eat and eat. It becomes our problem when they leave the Alder forest and head into our gardens. Their favorite exotic treats seem to be the leaves of apple and cherry trees and roses. Any leafy thing in your veggie garden will also do. At Bayview Farm & Garden, we can show you how to protect your garden plants in a non-toxic way.

I just wanted to offer this perspective to help us get through caterpillar season with a little more understanding of the place we live. But brace yourselves…it will probably be worse next year and possibly the next after that. They haven’t peaked yet. Btw, if you see a little white dot on the back of a caterpillar’s head, that is an egg from a beneficial predatory wasp, whose population ebbs and flows opposite the tent caterpillar. You might want to leave it alone as the wasp has plans for this one…but that’s another chapter….