Tomato Hornworm

The tomato hornworm is a common pest of tomato plants as well as peppers, eggplant and potatoes.

tomato_hornworm_pupa

Like all insects, the tomato hornworm goes through four developmental stages—egg, larva, pupa (left) and adult, which is the five-spotted hawk moth.

It's the larval stage of the tomato hornworm that does all the damage. The pale green caterpillar—with a black horn on its rear end—voraciously gobbles up the leaves and stems of tomato plants. At first quite small, the caterpillar goes through several instar stages and, in a month's time or less, measures some 3-1/2 to 4 inches long.

Monitor your tomato plants for small green caterpillars during July and August. Hornworms can be hard to spot because they're so well camouflaged, especially when small. Hand-picking or an application of Bt (Bacillus thuringiensis), the nontoxic product that's also used to kill mosquito larvae, are both effective controls.

The tomato hornworm's worst enemy in the garden is a small parasitic wasp, which lays its eggs inside the caterpillar. The wasp larvae then feed on the hornworm. If you see a hornworm with white projections on its body, leave it alone and don't kill it; Mother Nature will do it for you.

Next Up

7 Ways to Prevent Tomato and Potato Blight

Early and late blight can affect both tomato and potato plants. Learn how to protect your garden and keep these diseases at bay by following these prevention tips.

Why Do Tomatoes Split?

When it comes to taste, homegrown tomatoes beat those hard, red supermarket orbs hands down. Learn why tomatoes crack and split and what to do about it.

Squash Bugs and Squash Vine Borers in the Garden

Having problems with your squash plants? It might be squash bugs or squash vine borers. Both can cause significant damage to squash, gourds, pumpkins and zucchini plants. Learn how to detect these pests and preserve your crops.

How to Get Rid of Grubs

Grubs feed on the roots of your lawn and plants. Take control before these destructive pests get out of hand.

How to Prune and Stake Tomato Plants

Try this advice on pruning, supporting and staking tomato plants for a healthier, more productive crop.

How to Ripen Green Tomatoes Indoors

Enjoy the fruits of your gardening labor by ripening green tomatoes indoors with these easy tips.

How Far Apart Should Tomatoes Be Planted?

Tomato plant spacing depends on a few factors, including the variety type and the type of garden. Follow our advice and you'll be spacing for success.

Humane Ways to Get Rid of Groundhogs and Keep Them Away

Got groundhogs? Discover effective, all-natural ways to keep these critters out of your yard and garden.

Deter Deer in the Garden

Learn how to keep deer from destroying your landscape and backyard garden.

How to Plant, Grow and Care for Tomatoes

Consider this your ultimate guide to choosing tomato plants, planting, growing and caring for tomatoes, and harvesting the best-tasting tomatoes ever.

Go Shopping

Get product recommendations from HGTV editors, plus can’t-miss sales and deals.

On TV

Follow Us Everywhere

Join the party! Don't miss HGTV in your favorite social media feeds.