what is eating my tomato plant stems

What’s Eating My Tomato Plant Stems? How to Identify and Stop These 6 Common Tomato Pests

As a home gardener few things are more frustrating than walking out to your vegetable patch and finding entire stems of your prized tomato plants chewed through or missing leaves and fruit. While you were eagerly watching your tomatoes ripen some nefarious critter was making an all-you-can-eat salad bar out of your harvest!

But before you resign yourself to a summer without homegrown tomatoes take heart. There are ways to identify what’s attacking your plants and protect them from further damage. Here are six of the most common tomato pests that may be chewing on your plants’ stems and how to stop them.

Cutworms

It is most often cutworms that are to blame when tomato stems are eaten or cut through. When these inch-long, round caterpillar-like larvae come out at night to eat seedling stems or stems of plants that are already there, They then hide underground during the day. People often notice the first sign when they wake up and find newly planted tomatoes lying on the ground with a clean cut through the stem. Some plants may have whole branches that are wilted or dead because their stems were eaten through at night.

The good news is that cutworms are easy to get rid of by taking precautions. When you first plant transplants, put a 3–4-inch cardboard collar around them. Or, wrap stems in aluminum foil or metal cans that have had both ends cut off. Cutworms can also be kept away by sprinkling diatomaceous earth around the bases of plants. Finding and destroying them around plants is key. Look under the trash near the damaged plants and break any that you find.

Tomato Hornworms

While cutworms nibble stems from underneath soil level, tomato hornworms aggressively munch foliage and damage above-ground parts of tomato plants. These huge green caterpillars have white v-shaped marks and a prominent horn on their rear end. They can quickly defoliate and even kill tomato plants if left unchecked. Besides leaves, they will also sometimes chew on upper stems.

Carefully check the upper parts of plants for hornworms daily during summer months. Look under leaves and on top of soil around plants. Pick off any you find and squish or drop in soapy water. Using Bt (Bacillus thuringiensis) is also very effective against these voracious pests. It’s safe for humans and beneficial insects but kills hornworms when they ingest it.

Click Beetle Larvae

Adult click beetles are not plant pests, but their wireworm larvae can do a lot of damage to tomato plants, like chewing through the stems. The larvae of the click beetle are grayish brown and live underground. They eat seeds, roots, and stems. Damaged plants may become stunted or wilt. Click beetle larvae may be found in damaged roots and under the soil near plants.

There are few chemical control options for wireworms. Practicing crop rotation is one of the best preventative measures. Nightshades like tomatoes, potatoes, peppers, and eggplant should not be planted in the same spot year after year. Using plastic mulch instead of bare ground can also keep people from getting to it. Diatomaceous earth around plants may provide some protection.

Stem Boring Insects

A variety of insects are referred to as “stem borers” because their larvae bore into and tunnel inside of plant stems as they feed. This damages vascular tissues and interrupts the plant’s ability to transport water and nutrients. Fully grown larvae then chew their way out, leaving behind significant destruction. In tomatoes, corn earworms are a common stem borer. You may notice sawdust-like frass around damaged stem areas.

It’s difficult to combat borers once they are inside stems, so prevention is critical. Be on the lookout for small holes in stems and any evidence of frass. Handpicking larger caterpillars is possible. Using row covers early on can exclude moths who lay eggs. Beneficial nematodes applied to soil kill larvae. Bt is also effective when sprayed on vulnerable stem areas where entry commonly occurs.

Flea Beetles

Tiny black flea beetles are notorious for chewing tiny holes in tomato plant leaves, but they don’t stop there. These small jumping beetles will also chew pits and wounds in tender stems if foliage is depleted. Heavily damaged plants become weakened and may wilt or suffer dieback. Flea beetles are especially problematic for young transplants.

Row covers are the best defense against flea beetles, excluding them from plants entirely. Diatomaceous earth around the base of plants also deters the beetles. Traps using yellow bowls of soapy water can catch some adults. Insecticidal soaps and neem oil sprays are also useful once beetles are detected on plants.

Rodents and Birds

Hungry rodents like rabbits, groundhogs, rats, and mice are all potential tomato stem chewers. Larger animals like deer may also nibble. Squirrels and birds can also sometimes damage tender upper stems and branches. Identifying these culprits means looking for other tell-tale signs like paw prints, droppings, or bite marks. Deer repellents using rotten eggs, hot peppers, or strong scents can be sprayed around vulnerable garden areas. Fencing and netting provide the best protection from hungry mammals. Scarecrows, reflective tape, and noisemakers may help deter birds. A garden cat is also a great way to scare off small rodents!

By identifying what pest is targeting your tomato plants’ stems and taking appropriate counter-measures, you can still enjoy a bountiful tomato harvest. Consistent monitoring, prevention tactics, and quick interventions when pests appear will keep your plants healthy and happy despite these common tomato nibblers. A little effort goes a long way when it comes to growing luscious tomatoes. Don’t let a few chewed stems stop you from succeeding!