This sphinx moth larvae is one of just a few insects that infest catalpa and can eat large quantities of leaves. The caterpillar is yellow with black lines and markings. The tree is regularly defoliated and often looks terrible by the end of the summer.
Catalpas are often planted to attract these catalpa "worms", a large caterpillar prized for fish bait because the skin is very tough and the caterpillar is juicy. The caterpillar can be frozen for use as a fish bait at a later time. The caterpillar can defoliate the tree once or twice a year but there appears to be no adverse consequences to the tree.