Invertebrates
Tomato Hornworm
Manduca quinquemaculata · also called five-spotted hawk moth
A gardener parts the leaves of a tomato plant to find a caterpillar as thick as a finger, already stripping the foliage bare and covered in tiny white cocoons that mean, quietly and without any drama, that the damage is about to stop entirely on its own.
Overview
The tomato hornworm, Manduca quinquemaculata, is a large, rapidly growing caterpillar found on tomato, pepper, and other nightshade-family plants across gardens and farmland throughout North America. Its capacity for quick, significant leaf damage and its dramatic transformation into a hummingbird-like sphinx moth make it one of the most recognisable and closely watched garden pests in North America.
A pest whose worst enemy hides inside it
Long before a gardener even notices the damage, a parasitic wasp may have already sealed a tomato hornworm’s fate from within, turning what looks like an unstoppable eating machine into a caterpillar quietly running out of time.
Status
Least Concern — widespread and common across suitable habitat with nightshade-family host plants throughout North America.
Tomato Hornworm: common questions
Is the tomato hornworm's horn dangerous?
No, the tomato hornworm caterpillar has a prominent horn-like projection near its tail that looks somewhat threatening but is completely harmless, unable to sting or bite, and serves no known defensive function beyond possibly startling a predator on sight.
What do the small white cocoons on a tomato hornworm mean?
A tomato hornworm caterpillar covered in small white, rice-like cocoons has been parasitized by a braconid wasp, whose larvae developed and fed inside the caterpillar before emerging through its skin to pupate, a process that usually results in the caterpillar's death shortly afterward.
What does a tomato hornworm turn into?
An adult tomato hornworm caterpillar transforms into a large, fast-flying sphinx moth, sometimes called a five-spotted hawk moth, which is often mistaken for a hummingbird as it hovers in front of flowers to feed on nectar at dusk.
How much damage can a tomato hornworm do to a garden?
A tomato hornworm caterpillar grows rapidly to a large size and can defoliate a tomato plant significantly within just a few days, making it one of the more damaging and closely watched garden pests for anyone growing tomatoes or related nightshade crops.