The Catalpa tree is the host for the larvae of the Catalpa Sphinx Moth- Ceratomia catalpae. Both the northern and southern Catalpa species are used by this moth.
The Catalpa Sphinx Moth can produce up to three generations each year. The eggs are laid in clusters on new leaves and hatch in five to seven days. The caterpillars begin their lives feeding en mass near the site where they hatched. Feeding of the young caterpillars is localized and leaf damage on a single branch may be the only sign the worms are there.
They are voracious feeders and where the moth is plentiful, the caterpillars can defoliate a tree. The Catalpa tree is a vigorous grower and has adapted to the moth. Defoliation by the worms is followed immediately by a new flush of leaves just in time to feed the next generation of caterpillars.
As the caterpillars grow, they shed their skins and crank up the feeding rate. They begin to eat many leaves each day, still feeding as a group.
When they shed their skin the last time they disburse throughout the tree and feed as individuals.
Why all this talk about a caterpillar? Catalpa Worms are an incredible fishing bait. The worms exude a strong smell when damaged and the aroma spreads in the water as well as the air. The skins are tough allowing each worm to catch multiple fish. Catfish and Bluegill find these worms to be irresistible and will bite these when nothing else seems to work. Almost all fish will eat Catalpa Worms.
The caterpillars can be harvested by laying a sheet on the ground under the tree and shaking the branches to knock the worms loose.
The Worms can be used fresh or can be frozen for later use. Fresh worms can be kept alive with fresh leaves to feed on. Live worms are eating machines and suffer quickly from a lack of food.
The worms can be flash frozen on a sheet pan in the freezer and saved for later use. Thawed worms seem to be equally as attractive as fresh worms.
Here are a couple of cultural hints for raising Catalpa Trees for worms.
First, lawn and garden pesticides, especially systemic pesticides, can be taken up by the roots of the trees and will kill the worms.
Second, do not harvest all the worms from your trees. Some will need to mature into moths to provide more worms in the future.
Third, the worms migrate to the ground below the trees and burrow into the soil to pupate and develop into adults. The ground beneath the trees should not be a hard sod of grass that the worms cannot burrow into. The best trees for worms have a loose weedy or leafy mulch beneath them that keeps the ground soft enough for them to burrow into.
Catalpa Sphinx Moths are capable of traveling long distances and worm production can be sporadic. Trees growing where conditions are good for survival of the worms seem to be more consistently productive.
To be sure, you can’t have your own supply of Catalpa Worms without Catalpa Trees.