8 Reasons Your Plant's Leaves Have Holes—and How to Fix Them

Holes in the leaves of your veggies, herbs, and flowers may be unsightly, but they are not necessarily alarming. Sometimes, holes in plant leaves are caused by beneficial insects, such as native leafcutter bees, which use leaves as building materials for their nests. Other times, it is leaf-eating pests such as caterpillars and slugs, plant diseases, or environmental factors that cause leaf holes.

Keeping track of when leaf holes appear, which plants are affected, and the size and shape of the holes on your plant will help you determine which of the following culprits is causing the damage and what, if anything, you need to do about it.

1. Slugs and Snails

If holes are appearing on your plants after dark, there’s a good chance you’re dealing with a slug or snail issue. Unlike most pests, slugs and snails are most active at night or in cool, wet weather.

Slugs and snails leave large, irregular holes on plant leaves, flowers, and fruit, as well as slimy, silvery trails of slime in their wake. These pests are particularly fond of plants in the Brassica family, as well as hostas, hibiscus, and tomatoes.

The Solution: Slugs and snails are tricky to spot as they’re mostly active at night. Create a simple “slug pub” to catch these garden marauders by filling an old plastic cup with stale orange juice and slightly burying the cup in the soil near damaged plants. Encircling plants and garden beds with copper tape or a line of crushed eggshells or baking soda may also deter slugs and snails.

2. Caterpillars

Many caterpillars don’t damage ornamental or edible crops and are an asset to gardens when they turn into moths and butterflies. One big exception is tomato hornworms and cabbage loopers, both destructive pests targeting tomatoes and brassicas. These caterpillars typically riddle plant leaves with lacy holes or chew entire leaves down to nubs. Unlike slugs and snails, caterpillars usually feed from the exterior of plant leaves rather than the centers, and they leave dark droppings instead of slime trails on plants after feasting.

The Solution: Cabbage loopers and tomato hornworms can be deterred with companion planting. Another way to get rid of them is hand-picking them and dropping them into a bucket of soapy water. For heavy infestations, use an insecticide containing Bt (Bacillus thuringiensis var. kurstaki) spray, but be sure to keep sprays away from milkweed and other plants that attract pollinators, because Bt harms other beneficial caterpillars such as monarchs.

3. Beetles

Like caterpillars, most beetles don’t cause a lot of garden damage; however, several beetle species will voraciously nibble on edible and ornamental plant leaves. The best way to determine which beetle species is causing damage is to consider what types of plants are being targeted.

For example, Japanese beetles often skeletonize the leaves of certain fruit trees, raspberries, and roses, while flea beetles bore small holes on nightshades (shown above) and brassicas, and cucumber beetles mostly feed on plants in the Cucurbit family.

The Solution: Regularly hand-picking beetles off your plants and dropping them into a bucket of soapy water can be an effective way to manage a small number of beetles. However, if you have ongoing issues with Japanese beetle infestations, applications of milky spore and companion planting can help you get ahead of pest issues, too.

4. Grasshoppers

Damage caused by grasshoppers closely resembles the damage caused by other pests and may look like ragged holes chewed in plant leaves or entirely skeletonized plants. However, these pests are more common in the Central United States than other regions; they often target alfalfa, soybeans, and grains, as well as garden plants like corn, carrots, and lettuce. Because they’re relatively large, it’s often easy to spot grasshoppers feeding on plants or jumping away when disturbed.

The Solution: Companion planting and hand-picking are organic methods to control grasshopper populations. Attracting birds with bird houses and feeders also reduces grasshopper infestations.

5. Earwigs

Slug and earwig damage often looks similar because these pests both chew ragged holes in plant leaves and do most of their feeding after dark. To tell the difference: check plants over carefully for slimy slug trails. Earwigs often leave dark pellet-like frass on plants when feeding, but they don’t produce any slime.

The Solution: Raking and cleaning up your garden will reduce damp, dark hiding places that attract earwigs. Alternatively, create a simple trap for earwigs by laying damp cardboard or newspaper near damaged plants, checking under these "traps" daily, and dispatching any earwigs you find.

6. Larger Animals

Deer, rabbits, groundhogs, and other furry garden visitors also sometimes feed on edible and ornamental plant leaves. However, these animals have much larger appetites than leaf-eating insects and will often take larger bites out of leaves—if they don’t eat the entire plant! Aside from their feeding damage, scat near your plants, garden fences, and knocked-over trash cans also indicates that larger animals are visiting your garden.

The Solution: Fencing is the most reliable way to stop larger animals, but deterrent sprays and companion planting can help too. To be effective, deer fences need to be at least 8 feet tall. To keep groundhogs and other burrowing animals out of your beds, fences need to be buried 1 foot or so in the soil.

7. Plant Diseases

While insects and animals are the most likely cause of plant leaf holes, plants sometimes develop leaf holes due to issues like shot hole disease and cercospora fungi. Shot hole disease typically affects fruit trees and almonds; it causes plant leaves to develop tiny holes that look like they were hit by a shotgun. Cercospora fungi, on the other hand, are most common on plants like Swiss chard and beets and often cause leaf discoloration in addition to small leaf holes.

The Solution: Fungal diseases thrive in gardens with poor air flow, so it’s important to follow proper spacing guidelines. Reduce fungal issues by growing disease-resistant plants, watering plants at the soil line, and cleaning up and destroying infested plant matter in the fall.

8. Hail and Other Physical Damage

Occasionally, plants may develop leaf holes and tears due to environmental factors. such as hailstorms and strong winds. This is particularly common if plants are growing up against fencing or trellises with sharp corners that may rip into soft leaf tissue. Unlike pest issues, environmental damage of this sort often affects just a few plant leaves at a time, and damage may be limited to the top or the side of the plant that’s located closer to a trellis or wall.

The Solution: Using soft or bendable plant ties and clips, and sanding off or placing soft covers over sharp points on fencing helps avoid some plant damage. If your plants are damaged by rough weather, prune away damaged stems and leaves to help your plants recover faster.