The green tomato bandit

Few garden pests can cause as much alarm, or overnight devastation, as the tomato hornworm. One day, you have a lush, towering plant loaded with green tomatoes. The very next morning, entire branches are stripped bare, leaving behind leafless stems, scarred fruit          and noticeable piles of dark droppings on the ground below. If you wake up to this kind of garden scene, you have likely been visited by this infamous pest.

Profile of a garden thief

Tomato hornworms (Manduca quinquemaculata) are the larval stage of the five-spotted hawkmoth. They are voracious eaters, feeding almost exclusively on plants in the nightshade family, which means your tomatoes, eggplants, peppers and potatoes are all on the menu. Because they grow so rapidly, a small handful of these caterpillars can defoliate an entire mature tomato plant in a matter of days.

Following the clues

Hornworms are among the largest caterpillars in Georgia. They can grow up to four inches long and as thick as your thumb, yet they remain masters of disguise. Their bright green coloring offers perfect camouflage against tomato stems, making them incredibly difficult to see.

When inspecting your plants, look for the bandit’s distinct features: a row of white, V-shaped stripes along its sides and a menacing, yet completely harmless, “horn” at the rear. If the caterpillar itself evades you, hunt for its calling card. Scan the lower leaves or the ground beneath your tomatoes for dark green or black droppings, known as frass. The hornworm is likely feeding right overhead.

Outsmarting the bandit

If you want to protect your harvest from this elusive thief, early intervention is your best defense. Here are the most effective ways to stop the bandit in its tracks:

• Hand-picking: Sometimes the old-fashioned way is best. Once you uncover their hiding spot, simply pluck the culprits from the leaves and drop them into a bucket of soapy water to end their crime spree.
• The midnight stakeout (The blacklight trick): Because they blend in so perfectly during the day, try hunting them at night. Grab a cheap UV flashlight (blacklight) and shine it on your plants after dark. Hornworms glow a bright, neon green under UV light, making them impossible to miss!
• Organic sprays: If you discover the plot early while the intruders are still small, organic sprays containing Bacillus thuringiensis (Bt) are highly effective. This targeted approach neutralizes the threat without harming your garden’s helpful insects.

Gardening in Middle Georgia always comes with a few surprises, and finding a stripped tomato plant is easily one of the most alarming. Fortunately, this elusive pest is no match for an observant gardener. By watching for early clues and heading out for a nighttime blacklight stakeout, you can stop the destruction in its tracks. Your plants will bounce back safely, leaving this notorious green bandit with absolutely nowhere to hide.

Morgan Durden works for the University of Georgia Cooperative Extension Service in Bibb County. The county office provides resources for gardeners as well as educational services and community support. Visit their office at 715 Oglethorpe Street, call them at 748-310-5350 or email their staff at bibb.extension@uga.edu.