Do Potato Bugs Bite

What is a potato bug?

The term “potato bug” refers to two entirely different insects in the US. Jerusalem crickets (Stenopelmatus fuscus) are large, biting insects native to the western US. Colorado potato beetles (Leptinotarsa decemlineata) are small striped beetles that defoliate potato plants across all 48 contiguous states. Only the Jerusalem cricket bites people — and only defensively when handled.

The confusion exists because both insects are found near soil and garden beds, and both carry the potato bug nickname depending on where you live. In California, Oregon, Washington, and the desert Southwest, “potato bug” almost always means Jerusalem cricket. In the Midwest, Mid-Atlantic, and New England, it almost always means Colorado potato beetle.

Knowing which insect you are dealing with determines whether you need to act at all.

Jerusalem cricket: the biting potato bug of the western US

Jerusalem crickets look alarming — they are large, naked-looking insects with a big round head, powerful jaws, and a banded golden-brown abdomen. Adults reach 1–2 inches long. They have no wings and move slowly on thick spiny legs.

Do Jerusalem crickets bite? Yes. They will bite if picked up or handled carelessly. The bite comes from their oversized mandibles, which they use to grind tough plant material and insect parts. The bite is painful — comparable to a wasp sting — but not venomous. There is no toxin, no venom gland. The pain comes purely from the mechanical force of the jaws. Swelling or redness at the bite site is a reaction to the bite itself, not a toxic injection.

Jerusalem crickets are nocturnal. You are most likely to encounter one when turning over a rock, board, or pile of garden debris. They do not seek out humans, do not enter homes to find food, and spend most of their lives underground.

Where Jerusalem crickets live:

• California, Oregon, Washington — very common
• Nevada, Arizona, New Mexico, Utah — present
• Eastern Rockies and Great Plains — occasional
• East of the Mississippi River — rare; not established

Colorado potato beetle: the pest that actually harms your garden

The Colorado potato beetle (Leptinotarsa decemlineata) is the serious garden pest. A small orange-yellow beetle with 10 black stripes, it is the primary defoliating insect on US potato crops. The USDA estimates it causes more than $500 million in annual crop losses to commercial and home gardens combined.

Do Colorado potato beetles bite? No. They have chewing mouthparts designed for eating leaves, not biting animals. If one lands on your skin, it feels nothing more than a light touch. They pose no threat to humans or pets.

What they do to potato plants:

• Adult beetles emerge in spring and begin feeding immediately on new growth.
• Females lay clusters of bright orange eggs on the undersides of leaves.
• Larvae (orange-red grubs with black spots) hatch in 4–9 days and feed more aggressively than adults.
• A single plant infested with 30–40 larvae can be defoliated in 10–14 days.
• After two larval feeding stages, pupae drop into soil to complete development.

Where Colorado potato beetles live: Every US state east of the Rockies has established populations. Western states have sporadic infestations from transported plant material. No US state is free from the risk.

How to tell them apart: identification guide

Jerusalem cricket identification:

• Large, 1–2 inches
• Round, oversized head with strong black mandibles
• No wings; thick, spiny legs
• Golden-brown body with dark brown banding across the abdomen
• Looks “naked” or alien compared to most insects

Colorado potato beetle identification:

• Small, 0.4 inch (about the size of a large ladybug)
• Rounded oval body, orange-yellow with exactly 10 black stripes on the back
• Wings hidden under striped shell; flies readily
• Eggs: small, bright orange-yellow, laid in neat clusters on undersides of potato leaves
• Larvae: plump orange-red grubs with 2 rows of black spots along the sides

Eggs of Colorado potato beetle are what most home gardeners first notice. They appear as small, tidy clusters of 20–30 orange eggs on the underside of potato leaves. Finding and crushing these eggs prevents larval damage more effectively than any spray.

Managing Colorado potato beetles without chemicals

Hand-picking is the most effective control for home garden scale. Commercial growers rely on insecticides, but home gardens rarely reach the beetle pressure that justifies spray.

Weekly inspection schedule:

1. Check undersides of every potato leaf from May through July.
2. Crush any orange egg clusters between your fingers or drop into a jar of soapy water.
3. Knock adults into soapy water — they are slow and fall easily.
4. Look for orange grub larvae near the growing tips; they feed most actively there.

Crop rotation: Move potato beds to a new location each year. Overwintering beetles emerge in spring and walk to where potatoes were grown the previous year. A 30-foot move between seasons significantly reduces spring emergence pressure. See companion plants for potatoes for planting combinations that may further reduce pressure.

Row covers: Install floating row covers at planting and keep them in place until flowering. Row covers physically exclude adult beetles from reaching plants. Remove covers during bloom for pollinator access.

Straw mulch: Research at Cornell University and Penn State found that thick straw mulch (4–6 inches) reduces Colorado potato beetle populations by 50–60% compared to bare soil. The mulch harbors ground beetles and spiders that prey on potato beetle eggs and larvae.

Jerusalem crickets: do they need control?

Almost never. Jerusalem crickets are generalist feeders that eat decaying plant matter, dead insects, roots, and other soil insects. They rarely damage living garden plants. Their role is closer to a soil decomposer than a garden pest.

In established vegetable gardens, Jerusalem crickets actually provide mild pest control by eating larvae and pupae of soil-dwelling insects, including some Colorado potato beetle pupae.

When Jerusalem crickets become a nuisance:

• Large populations can damage seedlings by gnawing on stems at soil level
• They occasionally damage strawberry runners and thin-stemmed transplants
• In large numbers, they can damage potato skins at soil level during tuber development

If you have a Jerusalem cricket problem in potato beds, the solutions are mechanical:

• Reduce moist hiding spots (woodpiles, dense mulch against stems)
• Hand-pick individuals found near seedlings and relocate them to a mulch or compost area
• Diatomaceous earth dusted at soil level deters movement but must be reapplied after rain

Related garden pests and how they compare

For other garden insects that confuse US gardeners, see vole vs mole for soil animal identification and slug vs snail for the snail-like pests that damage potato tubers directly.

Colorado potato beetles are one of several soil-dwelling insect problems in potato beds. For broader pest management in garden beds, see how to get rid of gnats in plants and borax for ants for related soil insect control approaches.

Protecting your potato harvest

The Colorado potato beetle is the insect that actually matters for potato growers. Management is straightforward at home garden scale:

1. Inspect weekly from May through July.
2. Crush eggs before they hatch.
3. Rotate beds every year.
4. Use straw mulch to suppress emerging adults.
5. Plant resistant varieties — Elba, Allegany, and Defender have documented Colorado potato beetle resistance in USDA Northeast trials.

For planting and harvest timing guides, see how to plant potatoes, how deep to plant potatoes, and when to harvest potatoes.

Penn State Extension maintains detailed Colorado potato beetle management guidance specific to US mid-Atlantic and Northeast growing conditions, including the most current information on insecticide resistance — an important consideration if chemical control becomes necessary.