Black and Yellow Worms (Catalpa Sphinx)

So it’s black and yellow and dangling from a leaf. Or maybe you saw it making its way up the trunk of tree and couldn’t help but wonder – “what kind of worm is that?” Well, that odd looking black and yellow worm is called “Catalpa Sphinx.” The Catalpa Sphinx is actually a common hawk or sphinx moth. It’s the larvae or caterpillar stage that you’re most likely to come across rather than the moth, which is dull and gray in color.

The real name for the caterpillar of the Catalpa Sphinx is “Catawba Worm” or “Catalpa Worm.” The Catalpa Sphinx occurs in most southern states and throughout the eastern part of the United States. So if you live in any southern state or anywhere from Florida to New York and west to Iowa, Michigan, Kansas and Texas, chances are that bright “worm” you saw was a Catawba or Catalpa Worm.


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The Catawba Worm feeds on Catalpa trees. Its appetite is so great that this pretty pest can strip an entire tree of its leaves. This can be a serious problem for Catalpa trees that provide shade or nursery stock, and Catalpa trees that are popular for their ornamental beauty. The Catawba does not feed on any other tree outside of the Catalpa tree, so these trees are subject to attack at all times. The larvae are currently considered a threat to the survival of the Catalpa tree. Catalpa trees grow in all of the states mentioned above as well as in central and south central states such as Illinois and Indiana, and south to Arkansas and Tennessee.

The four life stages of the Catalpa Sphinx include the egg, larva, pupa, an adult. The larva (the worm) is white to pale yellow and it has a black spine and a horn on its rear. When the larva begins to develop, the colors change slightly. The head turns completely black and the body remains pale yellow in color but black markings develop all over the body. The pupa is reddish brown, and the moth, as mentioned earlier, is gray.

Because the Catalpa tree is considered a prized tree, known for its shading capabilities and its status as an ornamental tree, many people consider the Catawba to be destructive with no real value to the environment. Because of this, pesticides are commonly used to control infestations. In addition to human threats, the Catawba worm is constantly under attack by the wasp. The wasp is actually a parasite that deposits its eggs through the skin of the Catawba. The wasp larvae actually feed on the insides of the Catawba, and when the wasps are ready to leave the host, they spin silken cocoons on the Catawba’s skin. An infected Catawba does not survive into adulthood.

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While many would say the Catawba worm is a pest, most fishermen would disagree. Catawba or Catalpa worms are extremely popular for fish bait.

Author: The Top Worm

1 thought on “Black and Yellow Worms (Catalpa Sphinx)

  1. crawling fast in my teak wood swedish cabinet of teak wood crawling on folded clothes on the cabinets teak wood.yellow gold ringed 4 inch worm rather thick and fast, healthy worm.
    I live in san diego CA.

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