Pupae are typically brown, two inches or more in length, and many have a pronounced “snout” off the head end.Īdult stages of hornworms are heavy-bodied, strong flying insects known as sphinx or hawk moths. Pupation occurs a few inches below the soil surface in a small chamber of packed earth. Although these two insects are considered garden pests, the majority of the more than 30 hornworm species found in Colorado are rarely observed and do not cause significant injury to plants.įull-grown hornworm larvae migrate from their host plant and dig in loose soil where they pupate. The most widely recognized hornworms are those that feed on tomatoes – the tomato hornworm and the tobacco hornworm. Characteristically they sport a flexible spine (“horn”) on the hind end, although in some species this is lost and replaced with an eyespot marking. Hornworms are among the largest of all caterpillars found in Colorado, some reaching lengths of three inches or more. Whitelined sphinx, a common “hummingbird” moth. Adult stages of hornworms are known as sphinx, hawk, or “hummingbird” moths.Although the “tomato hornworm” damages garden plants, most hornworm species cause insignificant plant injury.Hornworms are among the largest caterpillars found in Colorado.

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