What Causes Holes in Tomatoes? Identifying Common Tomato Pests
Nothing disappoints a tomato grower more than finding holes and decay in your ripening tomatoes. After months of tending your plants, it’s frustrating to have your harvest ruined right before picking time. So what causes these unsightly holes and internal rot in tomatoes?
There are a few common tomato pests that can invade fruits and leave holes, tunnels, and rot inside. By identifying the culprit, you can take steps to prevent further damage and save the rest of your crop. Here are some of the most likely suspects behind holes in your tomatoes:
Tomato Fruitworms
Tomato fruitworms, also called corn earworms or armyworms, are probably the most common cause of holes in tomatoes. These green, brown, or yellow striped caterpillars chew their way into fruits, leaving holes on the surface and tunnels inside tomatoes.
You may notice holes in green tomatoes that expand as the fruits ripen. Shallow tunnels often lead to soft rotten spots beneath the skin. Severe infestations can ruin most of a plant’s tomatoes.
The adult fruitworm is a nondescript tan and grey moth. It lays eggs on tomato plants, which hatch into ravenous caterpillars. Controlling them early by spotting eggs or small worms is key.
Tomato Hornworms
Tomato hornworms are large green caterpillars with white V-shaped markings and a horn on their rear end. These oversized worms feed on foliage and also chew into tomatoes, leaving large holes and scars on fruits.
Their holes tend to be larger than those created by fruitworms. You’ll often see frass (caterpillar poop) around feeding sites. Hornworm damage is easy to diagnose due to their size. Just check under leaves to spot these 4-inch beasts.
Stink Bugs
Various stink bug species can puncture tomato skins with their sharp mouthparts to suck juices from fruits. This leaves small holes that often turn into sunken soft spots. Beneath holes, you may find yellow discoloration in the flesh.
Stink bugs hide on the undersides of leaves and stems. Crushing one releases a foul odor that helps identify these pests. Their shallow holes differ from the deeper tunnels of worms.
Cutworms
Cutworm caterpillars emerge at night to feast on tomato plants. They often gnaw through stems at soil level, killing the entire plant. But they also create holes in fruits touching the ground. Their damage is often limited to low-hanging tomatoes.
Blossom End Rot
Not all tomato holes are caused by pests. Blossom end rot results in sunken brown leathery spots at the base of tomatoes. As the spots enlarge, holes can form, exposing the flesh inside.
This disorder is triggered by calcium deficiencies and/or uneven moisture. Improving soil nutrients and watering consistently can help prevent it. Holes from blossom end rot start at the blossom end rather than randomly over the surface.
Preventing Holes in Tomatoes
The first step in preventing internal-feeding pests is rigorous tomato plant inspections. Check undersides of leaves for eggs, worms, stink bugs, or other pests. Catch infestations when they first start.
Cover plants with row covers or fine mesh to exclude moths and bugs. Support plants with stakes and prune leaves to prevent contact with the ground.
Apply Bacillus thuringiensis or spinosad at first signs of worms. Handpick larger hornworms or use traps for stink bugs. Keep plants healthy with adequate fertilization and moisture.
Destroy tomatoes with holes or rot to prevent further insect damage. Pick all ripe tomatoes promptly so worms can’t invade them first. At season’s end, dispose of heavily infested plants.
Common Tomato Holes vs Rare Problems
While pests cause most holes in tomatoes, other disorders can also be to blame in some cases:
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Dry soil leads to cracking and split skin, which provides entry points for decay.
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Early blight, a fungal disease, creates small dark spots on tomato skins. These may turn into holes.
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Blossom end rot is more common than other nutrient deficiencies that can cause holes at tomatoes’ shoulders.
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Rodents like squirrels, rats, or mice may take occasional bites from fruits. Monitor for signs like teeth marks.
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Bird pecks typically occur on fully ripe red fruits. Cover plants with netting if birds are a problem.
The pattern, location, and timing of damage provide clues to distinguish between pest feeding and other issues. Careful inspection of plants helps pinpoint causes accurately.
Don’t Let Pests Win
A few tiny worms or bugs can wreak havoc on tomato plants if left unchecked. But attentive gardeners can outsmart these pests. Combining physical barriers, natural pest control, and prompt removal of infested fruits limits holes in tomatoes caused by invasive insects.
With quick identification and action against early signs of invaders, you can still harvest plenty of flawless tomatoes. Don’t let fruitworms, hornworms, or other tomato pests get the upper hand. Stay vigilant and use multiple strategies to protect your plants from decline.
What’s wrong with my tomatoes?
Even the best-cared-for tomato plants can be plagued by problems once in a while. Diagnosing the culprit is the first step to a solution. To help you keep your tomato plants from having these six problems, here are some things you can do today.
Blossom end rot is when the bottom of a tomato turns black and turns into an ugly, leathery spot. It happens because developing fruit doesn’t have enough calcium because plants can’t take in calcium when they’re dry. You can eat the fruit but may have to cut off a good portion of it.
- Water regularly and use a fertilizer that contains calcium.
- Add a couple of inches of organic mulch around the plants to keep the soil evenly moist during the growing season.
- Check the pH of the soil—it should be between 6 and 8. 5 to 7 is best. If it is too high or too low, blossom end rot could happen.
Look for a black hole near the base of the fruit stem when you go to pick your tomatoes. That’s a sign of tomato fruitworms (Helicoverpa zea). Cut the tomato open and youll see tunnels — you might even find the culprit there, too. The tomato fruitworm is a caterpillar that is 1 ½ to 2 inches long and can be light green, brown, or black, with stripes going down its body. When it’s fully grown, the larva falls to the ground to pupate. After a few weeks, it comes out as a yellow-tan moth and lays eggs on tomato leaves to begin the life cycle all over again. The fruit is usually a mess once fruitworms have been visiting so you wont want to eat it.
- It is possible to stop the tomato fruitworm from reproducing by throwing away infected fruit before the caterpillar comes out.
- To try to find pupae that are overwintering, till the soil in the fall.
- Try Bt (Bacillus thuringiensis). It’s an organic bug killer that works on caterpillars and won’t hurt food. Just be sure to wash fruit thoroughly before eating. But Bt can also kill butterfly larvae, so don’t use too much of it if you know you want caterpillars.
Around the beginning to middle of summer, these big (up to 4 inches long!) caterpillars can quickly eat a plant’s leaves and may even eat green tomatoes. Small tobacco hornworms (Manduca sexta) are plain yellow or white with no markings. As they get older, they turn green over time and get white stripes and the “horn” that gives them their name on the last part of their abdomen. Tobacco hornworms are the larvae of the sphinx moth.
- If there aren’t many, pick out the caterpillars by hand and drop them in soapy water to kill them.
- Plant sweet alyssum (Lobularia maritima), dill (Anethum graveolens), or Shasta daisies to get braconid wasps. The wasps will lay eggs on the tomato hornworm, which will then eat the wasp and kill it.
- Bt is also effective. Thuricide®, which has the kurstaki strain of Bacillus thuringiensis in it, kills tobacco hornworms well and can be sprayed up until harvest time. Just make sure to wash fruit well before eating it.
Tomatoes get cracks or splits when the weather goes from dry to wet or when you water them infrequently. This is because the plant suddenly needs more water, which makes the skin split. The tomatoes dont look good, but you can still eat them.
Tomatoes do best with 1 to 1½ inches of water a week. To keep plants from cracking and splitting fruit, water them often during the growing season and cover them with an inch or two of organic mulch, like straw or bark chips.
Late in the growing season you may come across tomatoes that look like this one. Its caused by stinkbugs feeding on the fruit. The spots are soft and spongy but superficial so you can still eat the tomato.
Does your garden have weeds growing next to your tomatoes? That’s where these bugs like to live, so getting rid of the weeds will probably get rid of the stinkbugs and leave your tomatoes alone.
This unusual-looking condition happens when flowers don’t develop properly. It’s usually caused by low nighttime temperatures (below 55 degrees) or strong winds. Catfaced tomatoes may look deformed, but they are still OK to eat.
Shelter plants from strong winds and protect them from low temperatures by covering them at night with row cover or an old sheet.
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Holes in Tomatoes? Two causes
FAQ
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