Attracting Catalpa Worms (Catawba Worms) to Your Trees

A reader planted two catalpa trees 15 years ago but has never seen the prized caterpillars (often called catawba worms) that are used as fishing bait. They wonder why some trees get worms and others don’t, and how to establish a population on their own trees.

Understanding the Life Cycle

The caterpillars are the larvae of the catalpa sphinx moth (Ceratomia catalpae). Female moths lay eggs on the leaves; once hatched, the caterpillars feed voraciously for about eight days, reaching up to 4.5 inches. Mature larvae crawl down the trunk and pupate in the soil at the base of the tree. The following spring, adult moths emerge, mate, and lay eggs on the same or nearby catalpa trees, continuing the cycle. In the Deep South, multiple generations can occur per year.

How to Introduce Catalpa Worms

1. Find a source tree that already has caterpillars. Ask at local bait shops or search for catalpa trees with visible larvae.
2. Collect caterpillars along with some fresh leaves. Place them in a paper bag (never plastic) with air holes punched in the top.
3. Transfer them to your tree’s foliage. They will begin feeding immediately.
4. Allow the cycle to complete – let the caterpillars mature, pupate in the soil, and emerge as moths that will lay eggs on your tree.

Note: Some trees may have genetic resistance that prevents caterpillars from establishing. Try introducing larvae from several different source trees to increase success.