If you’ve noticed holes, notches, or a general disappearance of your potato plant’s foliage, you’re likely wondering what’s eating your potato leaves. This common garden problem can set back your harvest, but identifying the culprit is the first step to a healthy crop.
Potato leaves are a favorite snack for a variety of insects and pests. The damage they leave behind is often a unique clue to their identity. Let’s look at the most common offenders and how to spot them.
What’s Eating My Potato Leaves
This section details the primary pests that target potato plants, organized by the type of damage they cause.
Chewed Leaves and Stems
These pests take big, obvious bites out of your plants.
- Colorado Potato Beetle: This is the most notorious potato pest. Adults are yellow-orange with black stripes. The larvae are fat, red-orange grubs with black spots. Both stages can defoliate plants rapidly.
- Tomato Hornworms: Large, green caterpillars that can strip stems and leaves. They blend in perfectly, so look for their dark droppings on leaves below.
- Cutworms: These gray or brown caterpillars hide in the soil by day and chew through young stems at night, often felling whole seedlings.
- Slugs and Snails: They leave irregular holes and a tell-tale silvery slime trail on leaves and soil, feeding mostly at night or on cloudy days.
Skeletonized or Lacy Leaves
These pests eat the green tissue between the leaf veins, leaving a skeletal framework.
- Flea Beetles: Tiny, jumping beetles that create a “shot-hole” pattern, which can merge into larger areas of damage. Severe infestations make leaves look lace-like.
- Potato Tuberworm Larvae: The larvae mine inside leaves, creating translucent tunnels or patches before skeletonizing them from the inside out.
Discolored, Curled, or Stunted Leaves
These sap-sucking pests weaken plants by feeding on their juices.
- Aphids: Small, pear-shaped insects (green, black, or pink) that cluster on undersides of leaves. They cause curling and can transmit viruses.
- Leafhoppers: Small, wedge-shaped insects that hop when disturbed. Their feeding causes “hopperburn,” a yellowing and curling of leaf edges that can look like a disease.
- Spider Mites: Nearly microscopic pests that cause a stippled, dusty yellow look on leaves. Fine webbing on the undersides is a clear sign.
How to Identify the Pest: A Step-by-Step Guide
Follow these steps to become a garden detective.
Step 1: Examine the Damage
- Large, irregular holes? Think Colorado beetles, hornworms, or slugs.
- Many tiny holes? Likely flea beetles.
- Leaf skeletonized? Could be severe flea beetle damage or tuberworm.
- Leaves curled and discolored? Check for aphids or leafhoppers.
Step 2: Check the Undersides of Leaves
This is where most pests hide. Look for eggs, larvae, insects, or webbing. Use a magnifying glass for small pests like mites.
Step 3: Inspect the Soil Surface
Look for cutworms, slugs, or their hiding places near the base of damaged plants.
Step 4: Visit Your Garden at Night
Some pests, like cutworms and slugs, are primarily nocturnal. A flashlight visit can reveal the hidden culprits.
Effective Control Methods
Once you’ve identified the pest, choose a targeted control strategy.
Manual Removal
For large pests like Colorado potato beetles and hornworms, hand-picking is very effective. Drop them into a bucket of soapy water. Check plants every few days, especially in early summer.
Barrier and Trapping Methods
- Row Covers: Lightweight fabric placed over plants prevents pests like flea beetles and leafhoppers from reaching them. Remember to remove for pollination if you’re growing a flowering crop, but potatoes are usually grown for tubers so covers can stay on.
- Copper Tape: Placed around raised beds, it deters slugs and snails.
- Beer Traps: Sink a cup of cheap beer into the soil to attract and drown slugs.
- Diatomaceous Earth: A fine powder sprinkled around plants. It scratches the bodies of soft-bodied insects, causing them to dehydrate. Reapply after rain.
Biological Controls
- Beneficial Insects: Encourage ladybugs, lacewings, and parasitic wasps by planting flowers like alyssum and dill. They eat aphids and other small pests.
- Bacillus thuringiensis (Bt): A natural soil bacteria that is toxic to caterpillars (like hornworms and young Colorado beetle larvae) when ingested. It’s safe for other insects.
- Nematodes: Microscopic worms applied to soil that target cutworm and other soil-dwelling larvae.
Organic and Chemical Sprays
Use as a last resort and always follow label instructions precisely.
- Insecticidal Soap: Effective against soft-bodied insects like aphids, leafhopper nymphs, and spider mites. It must contact the pest directly.
- Neem Oil: A botanical oil that disrupts the feeding and growth of many pests, including beetles, aphids, and mites.
- Spinosad: A natural substance derived from soil bacteria that is effective against caterpillars, beetles, and thrips. It’s very gentle on most beneficial insects when dry.
Prevention is the Best Medicine
Keeping pests away in the first place saves alot of trouble later.
- Crop Rotation: Never plant potatoes (or tomatoes, eggplants, peppers) in the same spot two years in a row. This breaks the life cycle of soil-borne pests and diseases.
- Keep the Garden Clean: Remove plant debris in the fall where pests can overwinter.
- Healthy Soil: Strong plants from compost-rich soil are more resilient to pest damage.
- Early Planting: Getting potatoes established early can help them outgrow some pest pressure later in the season.
- Companion Planting: While not a magic fix, interplanting with repellent plants like marigolds, coriander, or tansy may help deter some pests.
Frequently Asked Questions
What is making holes in my potato leaves?
Holes are usually caused by chewing insects. Large, ragged holes point to Colorado potato beetles, hornworms, or slugs. Many small, shotgun-like holes are the classic sign of flea beetles.
How do I stop bugs from eating my potato plants?
Start with identification, then use the least invasive method first. Combine manual removal, barriers like row covers, and encouraging beneficial insects. Resort to organic sprays like Bt or neem oil if infestations are severe.
Are potato leaves eaten by any animals?
Yes, sometimes. Deer, rabbits, and voles may eat potato foliage. Fencing is the best solution for animal problems. Damage from animals is often more substantial and clean-cut than insect damage.
Can plants recover from pest damage?
Potatoes are remarkably resilient. If you control the pest and the plant is otherwise healthy, it will often produce a decent crop even after significant leaf loss, especially if the damage occurs later in the season. Young plants need the most protection.
What eats potato leaves at night?
Cutworms, slugs, and snails are primary nighttime feeders. Also, adult Colorado potato beetles and hornworms may feed at night during very hot weather. A flashlight inspection will show you whose responsible.
Finding something eating your potato leaves can be frustrating, but don’t lose hope. By carefully observing the damage and the pest itself, you can choose an effective, targeted response. A combination of vigilance, prevention, and gentle interventions will keep your potato patch healthy and productive, leading you to a great harvest come autumn. Remember, a few holes in the leaves is normal and won’t nessecarily hurt your final yield.