What Are Catalpa Worms?

catalpa worms

Alabama has a booming bug population that includes thousands of creepy crawlers! Some of them are commonly known, like Brown Recluse Spiders, while others are completely unknown to the general population. One bug that many locals have seen before, but know little about, is the catalpa worm—which surprisingly isn’t a worm at all.

Today, we’re giving catalpa worms the spotlight they deserve. Some people consider them to be annoying yard pests, but catalpa worms play an important role in our ecosystem. Keep reading to learn more about catalpa worms, and why you’re seeing so many in your yard!

From Catalpa Worm to Sphinx Moth

Generally, when someone references a catalpa worm they’re probably talking about a catalpa sphinx moth—but in its pupal stage. Here’s a brief summary of the emergence and feeding of catalpa worms.


Typically, catalpa worms will hatch from their eggs around mid-May each year. Since catalpa sphinx moths lay 100 to 1,000 eggs at a time, it’s not uncommon for catalpa worms to suddenly appear in large numbers. After emergence, there are usually 2 to 3 more generations of worms born during the summer.


Catalpa worms got their name from their eating habits, as they feed exclusively on the leaves of catalpa trees. Newly hatched catalpa worms feed together in groups––stripping trees completely bare.

Where Are Catalpa Worms Found?

Catalpa worms can be found throughout the entire eastern side of the United States––from Texas to the Atlantic Ocean. Their population is often concentrated in the southern states, but you can sometimes find them as far north as New York. 

These caterpillars usually remain close to the catalpa trees that they feed on. Once the fall weather starts, catalpa worms will burrow a few inches into the soil, beneath catalpa trees, until winter weather has passed. In some instances, if winter weather is mild enough, these caterpillars will remain active around the trees. 

What Do They Look Like?

Catalpa worms are easy to spot because of their high-contrast coloration. Unlike fully matured caterpillars, newly hatched worms are in what’s known as the pale phase. They are mostly white in color with a few specks of black down the spine. 

Once fully mature, the caterpillars have a solid black head and a wide strip of black down the entire back of their body. The sides and belly of a mature catalpa worm are bright neon green or yellow in color. Catalpa worms also sometimes have a black horn at the end of their back. 

Another physical feature of catalpa worms to look for is their legs, or prolegs, as they’re traditionally called. These tiny nubs protrude out from the bottom of its belly, and function like real legs. They have suction-like qualities that help the worms grip surfaces.

Wasps: The Biggest Predator

One very distinctive feature for some unfortunate catalpa worms is a ridge of white wasp eggs along the back. Wasps are a catalpa worm’s biggest predator, and oftentimes female wasps will attach themselves to catalpa worms and insert their eggs just underneath their skin. 

There, the wasp larvae grow and begin to feed until they finally kill the catalpa worm.

Summer Pests Bugging You? We Can Help!

Though catalpa worms are docile in nature, they can wreak havoc on the trees in your yard. You’ll want to get rid of these worms before they destroy your trees! At Vulcan Termite & Pest Control, we’ve helped many homeowners rid their yards of all kinds of pests. We can help you, too. For more information, contact us today.