Identify And Control HornwormsThis page listed under Garden Pests Hornworms: They can be dangerous to members of the curcurbit family like the muskmelons, summer squash, winter squash, cucumbers and watermelon plants. They are large and pale green caterpillars with white and black markings that can reach up to 4 inches long when mature. There are two types of these worms: the tobacco and the tomato . The best way to distinguish one from another is to examine the stripes on the adult caterpillars. The tobacco species is more common in garden. Its range comes from Southern Canada to Argentina. It can be distinguished by its seven diagonal white stripes and its red ‘horn’. Its plant hosts include tobacco, tomato, eggplant, pepper and some weedy plants. 
Photo Credit Flickr randomduck's photostream Tomato types extend from Southern Canada to the Southern United States. It is distinguished by its eight-angled stripes pointing toward its head. Its horn is black projecting from the rear end. They are the biggest caterpillar seen in a landscape. Their lifecycle start from the egg. In late spring, adult moths lay eggs on the underside of the tomato leaves. The eggs mature and hatch in 6 to 8 days and become a larva. The larva undergoes 5 or 6 stages and reaches its full growth in 3 to 4 weeks. It then digs into the soil for transformation into the pupal stage. The pupa remains buried in the soil all throughout the winter. The adult moth emerges in the next spring or in two to four weeks if the weather conditions are desirable. The adult that newly emerges finds its way into the soil surface to mate, and deposits the eggs on the tomato plants for the next hatch. The adult tomato hornworm is termed Sphinx moth or Hawk moth. Its color is mottled gray-brown with yellow spots on the sides of the abdomen. Its wing can spread up to 5 inches wide. The body size can be between medium to large and heavy with narrow front wings. Tomato hornworms have 5 less distinct orange spots on both sides of their abdomen. The tobacco hornworm moth has 6 orange spots on each side of the abdomen. Its hind wings are less distinct and have jagged lines. Both the tomato and tobacco variety feed on the new stems and leaves of tomato plants. The leaves are stripped off the vines in some cases. In some situation, even tomato fruit is eaten from its exterior part. How To Control Hornworms The best way to control hornworms is to pull them off from tomato plants. Also, planting dill near the tomato plants is effective. Dill plant such as basil or borage is a natural repellent to the garden pest. |