Caterpillars everywhere - Ask Extension
A black caterpillar with yellow/orange stripes down the length of its body has suddenly appeared in huge numbers. What is it? Is it harmful?
Knowledgebase
Caterpillars everywhere #939340
Asked July 15, 2026, 9:06 AM EDT
A black caterpillar with yellow/orange stripes down the length of its body has suddenly appeared in huge numbers. What is it? Is it harmful?
Franklin County Ohio
Expert Response
Good morning and thank you for your question. The Catalpa sphinx caterpillar (also known as the catalpa hornworm) is the larval stage of the catalpa sphinx moth and the exclusive consumer of catalpa tree leaves. In Ohio, there are two overlapping generations per year, with caterpillars frequently appearing from late May through early autumn.
They are not dangerous and typically do not require pesticides as they are well maintained naturally by biological control. Here is a blog post for further reading: https://bygl.osu.edu/node/767
Please let me know if you have any further questions. Thanks.
Jen
They are not dangerous and typically do not require pesticides as they are well maintained naturally by biological control. Here is a blog post for further reading: https://bygl.osu.edu/node/767
Please let me know if you have any further questions. Thanks.
Jen
