Tomato-Eating Caterpillars

Hornworms

• Hornworms are the caterpillars of sphinx moths. They grow incredibly large, often reaching lengths of 4 inches or more. These caterpillars range in color from white to green, depending on their stage of development. Hornworms grow an unmistakable sharp projection on their posterior. Older hornworms show the most interest in fruit. Due to their large size, they are easy to spot on the underside of tomato foliage.

Minor Tomato Eaters

• Armyworms are casual tomato eaters, preferring to chew on the outside of fruit. Armyworm damage tends to dry out quickly and scar. Cutworms feed on fruits that are touching the ground; they do not climb up the plant to feed. Tomato fruitworms often tunnel inside tomato fruits to feed, leaving contaminated water pockets in the fruits and rendering them useless.

Cultural Controls

• Hand-picking worms is always the safest way to control them. Check the underside of leaves for worms, then remove them by hand and drop them in a bucket of soapy water. Minor infestations are often naturally controlled by parasitic insects, especially in the case of hornworms. Cutworm damage can be controlled by trellising fruit and pinching tomato plants so that branches begin higher on the vine.

Bacillus Thuringiensis

• When infestations are out of control and tomato-eating caterpillars outpace your tomato production, it's time to consider stronger solutions. Bacillus thuringiensis (Bt) is a bacteria that is especially detrimental to caterpillars. It is relatively safe for other insects, including beneficials. Bt takes several days to begin to work, since it must be ingested and travel through the caterpillar before it becomes effective. Thoroughly treat tomato plants with Bt every week until you no longer see caterpillars feeding.