Tomato Hornworm Pest Control Information
By Barbara Fahs, Garden Guides Contributor
About Tomato HornwormsIf you look closely at a tomato hornworm, they are actually pretty. But the damage they cause is not pretty. They can leave your green tomatoes full of large holes, which cause them to rot. The hornworm is a large, pale-green caterpillar up to four inches long with a "horn" on its rear segment.
Prevention and ControlHandpicking is the most effective remedy. Whenever you see a worm or its droppings (you'll know there is a worm nearby above it), pluck it off your plant and destroy it.
Affected PlantsThe tomato hornworm can attack your eggplant, bell peppers and potato plants but is most common on tomatoes.
DamageIn addition to the fruit, hornworms also feed on leaves and stems, which they can quickly defoliate.
Predator InsectsSeveral parasitic insects, such as wasps, feed on the tomato hornworm. If you see a worm with protruding white projections, leave that one because the wasp will kill it and then move on to another worm that you might have missed.
Natural InsecticidesIf you spot them while they're small, Bacillus thuringiensis (Bt) is an effective natural remedy for hornworms. Larger worms, unfortunately, are usually not killed by this bacterial product. You can use it preventatively.
Other Methods of ControlAfter your summer tomatoes are finished producing, Roto-tilling the soil destroys pupae that might be present. Chemical insecticides are also effective but usually not necessary, because the large size of the hornworm makes it fairly easy to find and destroy.