Tomato Plants Infested With Small Green Worms

Types of Green Worms

• To say that a tomato plant has green worms is a little bit ambiguous, because there are actually several types of green worms. They are usually all grouped together as simply "green worms" because they can be controlled in the same ways. The hornworm is a bright green and segmented caterpillar. You can distinguish the hornworm from other green worms by its reddish horn. Another caterpillar that poses a threat to the tomato plant is the fruitworm. The fruitworm larvae have yellowish bodies and black heads sporting bristles. As they begin to mature and grow, they change colors. Sometimes they are black but most often green. The bristles at the head are retained as they grow, and they typically have black spots. Tomato pinworms, cabbage loopers, and tomato cutworms are other types of green worms. All these green worms are usually located on the lower side of leaves. They are hard to see because their color blends in, so plant damage is the most obvious sign of their presence.

Green Worms and Tomato Plant Damage

• Because green worms are so difficult to spot, damage to leaves and fruit is the best indication of a tomato plant infestation. You'll notice holes in leaves and jagged edges where worms have been feeding. If they get into the fruit itself, they can be difficult to find. There might be holes in the skin of the tomato, but often they are so small that the tomato looks normal and healthy from the outside. Once the larvae are inside, they can burrow and hollow out portions of the fruit, and cause early ripening. If you cut a tomato open and the fruit seems to be watery and falling apart, this is a sign of a tomato plant infestation even before you have spotted the larvae. You also may find the shed skins of these caterpillars and frass, or droppings, within the interior.

Preventative Measures

• There are a number of preventative insecticides that can be purchased to ward off green worms online or where gardening supplies are sold. Other than using one of these preventative insecticides, the best precaution you can take against green worms is simply keeping an eye out for them. As soon as you spot one, pick it off the plant and kill it. If you walk through your garden regularly and inspect the plants, you might spot them on the leaves before they burrow into the fruit and ruin it. After harvesting tomatoes, stirring the soil will kill pupae that will become a problem later on.

Controlling Green Worms

• There are certain measures you can take to eliminate particular types of green worms. For example, pheromone traps, which attract and capture males, will help with the tomato pinworm by interrupting the breeding cycle, and a population of various natural enemies will keep other kinds of green worms in check. The fact is, you may not be able to see and identify the type of green worm you are dealing with. The best thing to do is take measures that will eliminate the main types of green worms across the board. An insecticide or biological spray should get your green worm problem under control, so you don't have to worry about tomato plant damage.