Virginia Cooperative Extension documents a long list of garden pests for Virginia, but only a handful feed on potato: Colorado potato beetle, flea beetles, aphids, black cutworm, Japanese beetle, tomato hornworm, tarnished plant bug, stink bugs, and thrips with spider mites. They arrive in waves tied to how far the plants have grown, not to a date on the wall. Cutworms and flea beetles tend to hit first, with Colorado potato beetle close behind.
Which pests attack potato in Virginia
The service that documents them is Virginia Cooperative Extension, and its list for Virginia gardens reads like a catalog of the whole vegetable patch: tarnished plant bug, aphids, black cutworm, cabbage looper, Colorado potato beetle, corn earworm and European corn borer, cross-striped cabbageworm, cucumber beetles, diamondback moth, flea beetles, harlequin bug, imported cabbageworm, Japanese beetle, Mexican bean beetle, squash bug and squash vine borer, stink bugs including brown marmorated, thrips and spider mites, and tomato hornworm.
Most of that list belongs to other crops. Imported cabbageworm, cross-striped cabbageworm, diamondback moth, cabbage looper and harlequin bug are named for the cabbage family, so they belong on a broccoli page. Cucumber beetles, squash bug and squash vine borer are vine-crop pests. Mexican bean beetle is a bean pest. Corn earworm and European corn borer are named for corn. Leave those off your potato worry list. A gardener who chases a squash vine borer in a potato row is chasing the wrong thing.
What stays are the insects and mites that plausibly reach potato foliage or the ground around it:
- Colorado potato beetle, the one on the list tied closely to potato and its nightshade relatives
- Flea beetles
- Aphids
- Black cutworm
- Japanese beetle
- Tomato hornworm, a nightshade feeder that can wander over from tomatoes
- Tarnished plant bug and stink bugs, including brown marmorated
- Thrips and spider mites
Extension documents these for Virginia gardens generally, and it does not rank them for potato on the pages this article draws on. A pest on the list is a pest that occurs in the state, not a pest guaranteed in your bed. Some, like the plant bugs and stink bugs, are more visitors than residents. The county office can tell you which ones actually show up near you.
When each one shows up, and what it does first
Start with the frost window, because everything else is counted from it. At the NAS Oceana weather station in Virginia Beach, NOAA NCEI Climate Normals put the 32F freeze probability in the 30-70% band at March 20 to April 3 (NOAA NCEI data for that station). Coastal Virginia Beach is the mild end of the state. The Blue Ridge and southwest Virginia run weeks later in spring, so every pest below shifts later with them.
The extension listing does not publish an arrival date for each pest, so treat what follows as an order of events, not a date list. It comes from how these insects generally behave.
Cutworms come first, around planting and emergence. The first sign is a young shoot lying on the soil, cut clean at ground level, often overnight. Flea beetles follow as the first leaves open. You see tiny round holes, like pinpricks from a shotgun, and the beetles hop when you brush the plant.
Colorado potato beetle arrives as plants leaf out. Watch for chewed leaf edges first, then clusters of orange-yellow eggs on the undersides. The larvae, which eat the most, come after the eggs. Aphids gather on tender new growth, and you notice curled leaves or a sticky film before you notice the insects.
The rest belong to a full, established canopy. Japanese beetles skeletonize leaves into lace. Hornworms are large enough to spot once leaves start vanishing, with dark droppings on the foliage below. Stink bugs and tarnished plant bug leave spotty, distorted feeding on leaves. Thrips and spider mites favor hot, dry stretches, and show up as stippled or bronzed leaves, sometimes with fine webbing.
The practical rule: count from your own emergence date, not the calendar. If you planted at the front of your local frost window, the early pests meet small plants. If you planted late, they overlap. The planting calendar counted back from your last frost shows how that date moves across the state.
Telling the damage apart from everything else
Many potato problems look like insect damage and are not. Water stress, nutrient shortage, disease and plain mechanical injury all produce holes, spots or yellow leaves. I can’t tell you what is in your garden, but I can give you the sign that separates the lookalikes. Check whether one plant or one side of a row went first, or the whole bed changed at once. Insects tend to start somewhere and spread. Weather, water and soil problems tend to hit everything together.
| What you see | Possible causes | What settles it |
|---|---|---|
| Shoots cut off at the soil line | Cutworm, or mechanical injury from a hoe or animals | A severed stem with the plant lying beside it; digging near the base may turn up a curled caterpillar |
| Small round holes in leaves | Flea beetles, hail, or a leaf disease where spots drop out | Tiny beetles that jump when disturbed; hail damage shows on every plant at once |
| Yellow lower leaves | Nutrient shortage, too much water, or normal aging | No chewing and no insects; a soil test through the county office |
| Wilting that recovers by evening | Water shortage | Dry soil when you push a finger in; insects do not cause this on their own |
| Stippled or bronzed leaves, fine webbing | Spider mites or thrips, or dry-weather stress | Webbing or tiny moving specks on the leaf underside under a magnifier |
| Spreading spots on leaf surfaces, tissue intact | Fungal or bacterial disease | No insect anywhere near the spots; a leaf sample examined by extension |
Turn leaves over. Look at the stem base. Check at dusk, since several of these insects hide by day. If the evidence is still unclear, bag a sample and take it to your Virginia Cooperative Extension county office rather than guessing.
What actually works here, and what is a waste of time
A physical barrier at the right moment beats any treatment. Cover the bed with floating row cover at planting, seal the edges, and keep it on through the early flea beetle and beetle window. Put the barrier on at planting, not after the first holes appear, because by then eggs are already laid. Set the bed on ground that did not grow potato, tomato, pepper or eggplant the year before, or overwintering beetles will emerge from under your cover.
Hand-picking works on a garden scale. Knock adult beetles and larvae into a bucket of soapy water and crush egg clusters on leaf undersides. Clearing weeds and old plant debris before planting takes away daytime shelter for cutworms. None of this costs more than a few evenings.
Season class matters too. Utah State University Extension and the University of Maine Cooperative Extension both publish potato varieties by early, mid-season or late class. An early class started at the front of your frost window gets tubers going before the summer feeders arrive, though a late freeze can still set young plants back. Our guide to potato varieties that suit Virginia covers how to choose. Use certified seed. Uncertified seed carries virus, and no spray fixes that after planting.
What does not work is spraying on a schedule without knowing what you have. A treatment aimed at the wrong pest does nothing to the right one, and broad sprays also hit the beneficial insects that eat aphids. Beetle traps hung near the garden tend to draw in more Japanese beetles than they catch. Delaying planting to dodge early pests pushes tuber growth into summer heat instead.
This site does not name pesticide products or doses. Virginia Cooperative Extension is the only place that knows what is registered for use in the state.
Where to check this for your own county
The authority to call is Virginia Cooperative Extension, through your county office. Every county has one, and its staff know which pests have been showing up locally and which controls are registered in Virginia.
Pest presence varies a great deal inside the state. Statewide documentation says these species occur in Virginia gardens. It does not say which ones are in your yard this year. The frost figure in this article comes from a Virginia Beach station, so a gardener in the Blue Ridge or southwest Virginia should add weeks to the spring sequence and expect the pests to shift with it. For the broader picture, see our overview of growing potatoes in Virginia.
Before you go, bag a fresh sample of the insect or damaged leaf, and take a photo of the whole plant plus the leaf underside. Then ask what was seen in your area last season and write the answer next to your planting date.
Common questions
What is the most common potato pest in Virginia?
The extension listing used here does not rank pests for potato. Colorado potato beetle is the one on the list most closely tied to potato and its relatives, but your county office can say what is most common near you.
Do I have to spray potatoes in Virginia?
Not automatically. Identify the problem first, since many lookalikes are not insects, and use barriers and hand-picking early. If a treatment is needed, Virginia Cooperative Extension can tell you what is registered in the state.
When do potato pests appear relative to planting?
Cutworms and flea beetles come first, around emergence, followed by Colorado potato beetle and aphids on young plants. Japanese beetle, hornworm and the mites and bugs tend to arrive on the full canopy. Count from your emergence date, not the calendar.
Does certified seed help with insect problems?
It protects against a different problem. Uncertified seed carries virus, and certified seed is the way to avoid that. It will not keep beetles off your plants.