Common Potatoes pests

The signature pest is the Colorado potato beetle, a rounded, yellow-and-black striped beetle whose orange, humpbacked larvae and clusters of orange eggs on leaf undersides can strip foliage fast. Potato flea beetles are tiny, dark, jumping beetles that chew small shot-hole pits in leaves, while potato leafhoppers are pale green, wedge-shaped insects that cause leaf edges to yellow and curl (a symptom often called hopperburn). Aphids, especially green peach aphid, cluster on new growth and are important because they spread potato viruses, and underground the potato tuberworm tunnels into tubers and wireworms bore narrow holes through them. Animal pests include voles and pocket gophers that gnaw tubers, plus deer that browse the tops.

Common diseases

Early blight (Alternaria) shows as brown spots with concentric rings, like a target, usually starting on older lower leaves. Late blight (Phytophthora infestans) is the most destructive disease and appears as fast-spreading water-soaked dark blotches with pale fuzzy growth on leaf undersides in cool, wet weather, and it can rot tubers. Common scab produces rough, corky patches on tuber skins, black leg and bacterial soft rot cause blackened, slimy stems and mushy tubers, and Verticillium wilt yellows and wilts plants from the bottom up. Viruses such as potato virus Y and potato leafroll virus, spread by aphids, cause mottling, crinkled leaves, upward-rolled leaflets, and reduced yield.

Prevention

Rotate potatoes and other nightshades (tomatoes, peppers, eggplant) so they do not return to the same bed for three to four years, and always start with certified disease-free seed potatoes. Choose resistant or tolerant varieties where available, give plants generous spacing for airflow, and hill soil over developing tubers to keep them covered and protected from greening and sunlight. Water at the base in the morning rather than wetting the foliage, keep beds weeded since weeds harbor pests and viruses, and remove and destroy volunteer potatoes and infected debris at the end of the season. Keeping soil pH slightly acidic and evenly moist during tuber formation helps reduce common scab.

Organic control

Hand-pick Colorado potato beetles, larvae, and egg clusters into soapy water starting as soon as plants emerge, since early removal prevents an explosion later, and consider floating row covers over young plants until flowering to exclude beetles and leafhoppers. Encourage beneficial insects such as lady beetles, lacewings, and predatory stink bugs, and use insecticidal soap or neem for soft-bodied pests like aphids and young larvae when populations climb. A Bt product formulated for the Colorado potato beetle (the tenebrionis or San Diego strain) targets young larvae, and yellow sticky traps help monitor and catch flying aphids and leafhoppers. For early and late blight, remove affected leaves promptly and apply a copper-based fungicide preventively during cool, wet spells, and always read and follow the product label for any spray you choose.

Scouting & monitoring

Begin scouting when shoots emerge and check at least weekly, looking on leaf undersides for orange Colorado potato beetle eggs and larvae so you can act before they defoliate plants. Watch for shot-hole flea beetle damage on seedlings, curled or yellowing leaf margins from leafhoppers, and aphid colonies on tender new growth. During humid or rainy stretches, inspect lower and inner leaves closely for the target-ring spots of early blight and the dark water-soaked lesions of late blight, since catching blight in its first days is critical. At harvest, examine tubers for scab, tunneling, and rot to gauge what problems to prevent next year.

Tips

Scout leaf undersides for beetle eggs and larvae every few days early in the season, because knocking them down before they multiply is far easier than fighting a heavy infestation. Plant certified seed, rotate away from other nightshades, and keep foliage dry to sidestep the diseases that cause the most trouble.

General home-garden IPM guidance, focused on prevention and least-toxic control. Always read and follow the product label for any pesticide, including organic products. Page updated Aug 4, 2026.