Hornworms, the larval form of hawk moths, are a common enemy of tomato plants. These plump, green pests are capable of quickly defoliating plants and will even attack tomatoes, leaving visible chew marks and holes in their midst. Fortunately for gardeners, hornworms are 3- to 5 inches long and bear a v-shaped design with a large hook on their bodies; they are easy spot if you know what to look for. While their size and appearance can be imposing, hornworms are harmless and can be removed without the use of pesticides.
Search your tomato plants regularly for signs of hornworms. Because of their chameleon coloring and markings, hornworms may initially be hard to spot since they blend in so perfectly. Focus your efforts on looking for signs of leaf damage and abnormally sparse foliage. Hornworms will also eat the fruit, so check both ripe and unripe tomatoes for chew marks and holes with a diameter of about 1 inch. More often than not, when this type of damage is found, hornworms can be spotted by visually scanning the plant.
Fill a bucket with water and add a few tablespoons of dish soap. Cut off the entire leaf or fruit with the hornworm still attached and submerge it in the bucket. Repeat this process as often as is needed. Dump out the water and discard the hornworms. This method does not harm your tomato plants, is environmentally friendly, and it eliminates the need to touch the hornworms at all.
Check plants frequently to ensure that the hornworm population has been eradicated. While tomato hornworm infestations usually only occur once per season in cooler climates, in warmer locales, hornworms can be present throughout the course of the year. In fact, hornworms can appear three or more times in the course of a growing season, which is why it is important to remain vigilant about keeping your tomato garden hornworm free.