What’s Eating My Plants? Identify Garden Damage Patterns + Quick Fixes

Scouting for Pests

Before you start scouting, remember: many insects are actually beneficial, so don’t assume every bug is bad news! Take the classic myth about peonies and ant—they’re usually just hanging out, not harming your plants. And never reach for an insecticide spray right away! Most sprays won’t touch the real pests but will wipe out helpful insects and natural predators. Plus, if you kill pollinators like bees, you could be signing your garden’s death warrant.

1. Leaf Miners: Tiny Tunnels, Big Trouble

•  Leaf miners are the fly larvae that tunnel between leaf layers in chard, spinach, lamb’s quarters, and beet greens—leaving pale, winding trails behind. You might not even notice them until you cook the greens and discover tiny worms inside. Yuck! Check out The Old Farmer’s Almanac’s tips for tackling leaf miners.

2. Cutworms: The Nighttime Seedling Snatchers

• Cutworms are sneaky night critters doing their dastardly deeds under the cover of darkness. These moth larvae emerge from winter hiding spots to feast on young seedlings and tender new plants. By morning, you might find your plants chewed off right at the soil line—just little stubs left behind. If you dig carefully around the base, you might even spot a fat, sleepy cutworm hanging out. Once found, you can remove the culprit however you like—garden justice is yours!

3. Slugs: Nighttime Leaf Eaters

Another nighttime visitor is the slug. If large, ragged holes are appearing in your hostas and petunia leaves, the slugs have been dining there. The holes should have irregular shapes due to the slugs’ file-like mouthparts. Small seedlings can be consumed entirely. Slugs can digest tissues from most plants, but you might find them especially liking plants with broad, delicate leaves, like beans, lettuce, cabbage, bok choy, and tomatoes. The only tip they leave is the silvery trails of dried mucus they slid out on. 

4. Aphids: Little Invaders With a Big Appetite

We’ve all seen green on plants in the springtime, but every summer we get a crop of red aphids on our heliopsis plants. They are easy to dislodge with a strong spray of water and usually don’t come back.

Green aphids are a familiar sight in spring, while red aphids often appear later, such as on heliopsis plants. These tiny sap-sucking insects can weaken plants but are usually easy to control by spraying them off with a strong jet of water. They rarely come back once dislodged, making this a simple, organic solution to protect your garden.

5. Butterfly Caterpillars: Beautiful but Hungry Guests

I love watching swallowtail butterflies flutter through the garden, but after hosting about 20 of their caterpillars, my dill patch has looked pretty ragged. These caterpillars feast heavily on dill and other herbs, sometimes leaving plants a bit bare. While they can cause noticeable damage, swallowtails are beneficial pollinators, so it’s best to tolerate some nibbling or gently relocate caterpillars if needed. Hopefully, your plants will have time to bounce back before harvest—like when the cukes are ready to pickle!

6. Cucumber Beetles: The Chewing Culprits

Ever seen this striped fellow below, who likes to chew holes in leaves? It’s the dreaded cucumber beetle. If left unchecked, they can defoliate young plants and spread bacterial wilt disease, which is especially damaging. Early in the season, protect cucumber and squash seedlings by covering them with lightweight row covers (like reemay) until they’re strong enough to withstand beetle attacks. I found our cucumber beetles at a loss, sitting on potatoes and tomatoes, not finding much to eat. This kept the population down a bit, so when we finally uncovered the plants as they started to blossom, they were not overwhelmed with bugs.

7. Squash Bugs: The Sap-Sucking Threat

There are a few squash bugs starting to show up and lay eggs on the underside of the zucchini leaves. Squash bugs are sucking insects that suck the sap out of leaves. They are fond of the young seedlings of squash and pumpkins, which are too young to withstand their attacks. If you catch squash bugs early, they cause little damage to plants in late summer and fall. The eggs hide under leaves; crush them or pick them and drop into a soaky bucket. Adult squash bugs are difficult to kill. Learn more about controlling squash bugs. 

8. Beetlemania: Tortoise, Flea, and Asparagus Beetles

• Tortoise Beetles with their shiny, hard shells quietly chew round holes in sweet potatoes, morning glories, tomatoes, and eggplants. The golden tortoise beetle looks almost gilded with gold—too pretty to squish, but they can cause damage.

• Flea beetles are tiny black hoppers that eat small holes in the leaves making them look like they have been hit with mini-buckshot. Their larvae, white grubs with brown heads, are 3/4 inch long - much larger than the adults. They live in the soil and eat plant roots.

• Asparagus Beetles come in two types: a black-and-white early spring beetle and a bright orange summer one that lays eggs on asparagus fronds. The larvae hatch into fat, slimy worms that can defoliate your plants quickly. To control them, shake the beetles into soapy water and handpick or crush the larvae. Don’t neglect your asparagus crop during summer! 

9. Colorado Potato Beetles

We went a little overboard on seed potatoes this year so we have beds of potatoes growing all over the garden. No potato bugs so far, but I keep checking. Colorado potato beetles will not only eat potatoes but also other nightshades, such as tomatoes, eggplants, peppers, and petunias—that is, most of my garden! Like the bean beetles, they lay masses of yellow eggs on the undersides of the leaves. When the brick red larvae hatch, they eat large amounts of foliage. By now you know the drill—handpick the adults and squish or drown them and their offspring. Learn more about deterring Colorado Potato Beetles.

10. Mexican Bean Beetles

While not yet a problem here, Mexican bean beetles are worth watching for. One female can lay over 500 eggs, and their larvae skeletonize bean leaves. Check the undersides of your bean plants for yellow egg clusters and crush them. Handpick beetles and larvae, then dunk or squish them to protect your harvest.

Watch for Plant Diseases, Too

While you are scouting, check for signs of plant diseases, too. Hot, humid weather is perfect for encouraging fungal and bacterial diseases, so watch those tomato leaves. Fungal and bacterial diseases can spread quickly. 

• For example, powdery mildew will start showing up soon, too. It looks like it sounds—as if someone sprinkled talcum powder on the leaves—and is especially common on tomatoes. See how to control powdery mildew.

• Cucumber wilt is another issue to watch for—if your cukes suddenly collapse and no amount of water revives them, it’s likely the work of cucumber beetle spreading this bacterial disease. Remove and destroy affected plants immediately, and try replanting in a new spot with lightweight row covers until flowering. Late plantings often escape damage.
• Blight, especially early or late blight on tomatoes and potatoes, is also common in damp conditions. It usually starts as dark spots on leaves or stems and can spread quickly. Remove infected leaves and avoid overhead watering to help slow it down. Learn more about tomato blight 

Be vigilant; if you stay ahead of the bugs, you will be able to keep them under control without resorting to using chemicals. 

🔎 Want to dig deeper? Visit our full Pest and Plant Disease Library for more organic solutions, pest profiles, and prevention tips.