Troubleshooting Potato Plant Problems

Potato gardening can be rewarding and successful. Plant potatoes in early spring after the final frost date has passed. Using disease-free seed potatoes will eliminate many potential problems.

Even when you have done everything by the book, as in life , gardening still throws obstacles in your path. The following is a compendium of common problems encountered when growing potatoes. If you are still having issues or have any further question , feel free to post your question on our facebook page.

Disease – Virus and fungal are the most common potato problems. Many diseases can be difficult to diagnose. For each particular disease, symptoms vary widely depending on stage of plant development at time of infection, climatic conditions and and other variables.

Most viruses cause assorted deformities, yellowing, browning, speckling, stunted growth and so forth. Absolute and 100% certainty in Identification of a particular disease can only be made with laboratory tests. These tests obviously are not feasible for home gardens.

Cultural ~ Nutrient Problems

1. Plants fail to emerge after planting potato slips.

A. The majority of store-bought potatoes are chemically treated to increase shelf life and prevent sprouting. Using certified seed potatoes will eliminate this problem.

B. Potatoes require a dormant or rest period and will sprout at a much lower rate if this period is prematurely broken. Cool temperatures or extremely warm temperatures are needed to nudge them out of their dormant rest period and allow potatoes to sprout.

Certified seed is always best to avert these problems. If you insist on using non certified seed potato , expect a lower rate of sprouting. Cut the seed potato so that there are at least two eyes on each piece. Plant after the last spring frost date in your area.

2. Green Potato tops ~ Green Potatoes.

The Tubers have been exposed to the sun during growing or following harvest. sunlight causes the tubers to concentrate chlorophyll which is visible as green spots on your spuds. Known as solanine, eating it will give you a belly ache as well as leaving a bitter tastes in your mouth. Make sure you keep potatoes well-covered while growing. Store them in a dark location, away from sunlight. See: Are Green Potatoes Safe to Eat ?

3. Tips of leaves and borders yellow, brown and die off. Potatoes have irregular brown spots.

Lack of water or inconsistent moisture during hot, dry weather is probably the cause. Water adequately. Placing a few inches of an organic mulch across planting bed will help conserve soil moisture as well as suppress weeds. Water the plants deeply when this happens, allow the soil to dry to a depth of about 4 or 5 inches between watering.

4. Potatoes are distorted -knobby-shaped and irregular sizes. Some have random brown spots

Inconsistent moisture, alternating wet and dry conditions will cause these symptoms. Keep soil evenly, moist. Slow deep watering on a regular schedule is best. Allow the soil to dry between waterings 4 – 5 inches. Mulch to conserve soil moisture. Plant potatoes closer together.

5. Hollow potatoes, cavities at the center.

Known as hollow heart, it occurs when potatoes grow too quickly. Excessive water and-or fertilizer is the cause. Cavity is sometimes discolored and encrusted with a powdery fungus.

Cut away any brown areas before using.

Fertilize properly – early in the plans development when tubers are forming.

Varieties resistant to hollow heart are frequently susceptible to other problems so searching for a resistant variety is futile. Simply adhere to proper gardening practices in the future.

6. Pink areas around potato eyes.

Pinkeye, it occurs on tubers in overly wet soil. It frequently progresses into a reddish brown decay. Planting in poorly drained soils is believed to be the cause.

See – Potato – Pink Eye or Brown Eye Cornell University

7. Foliage is greener than usual on top, no potatoes develop.

Temperatures are probably too warm. Potatoes require nights at or below 55 degrees F for good tuber production.

8. Stems have irregular dead streaks.

Manganese level in acid soils may be too high.

Excessive Manganese level is harmful to root crops such as potato, beets and carrot.

If after a soil test this is the issue then apply lime to reduce manganese levels.

9. Foliage turns a lighter green than normal, wilting and drying. Potatoes are watery and brownish.

Potatoes have proably been exposed to hot dry weather. Screening the plants during heat waves will help curtail this. Do not leave harvested potatoes exposed to the hot sun.

10. Roots are growing from inside the potato tubers , They have brown streaks.

there is a strong likelihood that “Nutsedge” has invaded your potato patch. It is a perennial weed that tends to grow in poorly drained areas. It reduces potato quality by penetrating tubers. Weed control is even more vital if this becomes an issue. Putting pictures of Nutsedge here would be of little value, as it looks just like a hundred other grassy weeds.


Plants are stunted; yellowish-black streaks inside stems.

Fusarium wilt is the likely culprit. It is a soil borne fungus. Fungal spores live in the soil. Remove and destroy infected plants. Rotate crops. Plant certified disease-free potatoes.

Fungicidefungicides for treatment of fusarium wilt for treatment of fusarium wilt will curtail the diseases spread, they will not cure an existing one, or repair damages already done.

Rotten Potatoes.

could be a number of problems, but Bacterial soft rot is a strong possibility. Rotting tubers are usually odorless in the diseases early stages, but develops a foul odor as secondary opportunistic organisms invade infected tissue. Soft rot can sometimes infect other parts of the plant as well.

Fungicides will not directly have any affect on the soft rot bacteria ,only the secondary opportunistic infections that follow.

Young sprouts cease growing and / or die back.

Possibilities include- Frost Damage or Blackleg and black scurf disease.

Frost damage naturally occurs if there was a frost following planting seed potatoes. No Rocket science here, you’ve lost those plants.

Blackleg is a bacterial disease which leaves sprouts rotting at soil level.

Black scurf is a fungal disease. The stems will have brownish indented spots just below the soil surface.

Remove and destroy any infected plants and tubers.

Roguing out blackleg-diseased plants and below ground segments reduces soil contamination but is only a useful practice if precautionary measures are taken to prevent contact of diseased tissue with other plants in your garden.

Young leaves cease growing, emerging leaves turn purplish and roll upward. Top leaves yellowing. Potatoes sometimes discolored

Potato Purple Wilt Top is the probable culprit. It is a viral disease akin to aster yellows and is spread by Leaf Hoppers

There is no adequate cure for this disease once contracted, destroy infected plants and control its spread by controlling leaf hoppers.

Dark brown scabby patches and spots on surface of potatoes.

Scab is caused by soilborne bacteria.

Potato Scab is suppressed at soil pH levels of 5.2 or lower. Sulfur will lower the pH and help correct this issue.

Irregular yellow patterns – visible in cool temperatures, not as visible in hot weather. Leaves are mottled and become crinkled.

Probably Mosaic Virus, which is transmitted by Aphids. There are several strains of the virus and no varieties are resistant against all mosaic virus strains.

Controlling Aphids is the key to controlling the spread of Mosaic virus. Rotenone or pyrethrum are generally used against these sap sucking insects.


Fine Webbing on under sides of leaves. Discolored shoots – pale yellow to white.

Spider Mites are a sap sucking insect.

Spraying with water will rid the plant of them -temporarily- use insecticidal soap or Rotenone for a more permanent control.

Leaves appear scorched and wilted. Coarse white speckles on upper leaf surface, borders sometimes turn yellow.

Good chance your plants are on the leaf hopper menu. Leafhoppers are green, yellow, or brown insects with wedge-shaped wings. They are sap suckers that transmit diseases and suck the life out of plants.

See Leaf Hoppers.

Large holes and chunks gnawed in fruits and leaves

The Tomato Hornworm is a destructive pest of eggplant as well as tomato, potato, and pepper plants. They consume leaves and stems as well as chewing pieces from fruit itself.

Handpicking is feasible, proper garden sanitation is essential to controlling any pest populations.

Spray with Sevin or pyrethrum .

Other insects could also be at blame if you are unable to locate any of the worms. Blister beetles are also known to chow down on potatoes and related crops.

Small round holes in foliage early in the season more prevalent on lower leaves. Check for Flea Beetles, tiny black beetles that feed on leaves and are common on eggplant. They not only attack eggplant, but also seedlings of tomatoes, potatoes, peppers, radishes, and corn

They generally jump when disturbed. Handpicking beetles in mild infestations is feasible. Keep the garden free of plant debris. Cultivate the soil deeply to destroy any larvae in early spring.

Cedarcidecedarcide insecticide is an effective deterrent of flea Beetles and a large array of other insect pests.

Large holes in leaves, Leaves are sometimes stripped bare – basically skeletonized

Probable culprit is the Colorado Potato Beetle, a black and yellow-striped beetle that feasts on eggplant, potato, tomato and related crops.

Bacillius thuringiensis is effective against the Colorado Potato Beetle. It will control early stages of the Colorado potato beetle and larvae.

Handpicking in mild infestations is feasible, however this pest has multiple generations annually – so while you’re handpicking there are more larvae developing beneath the soil surface. Cultivate the soil deeply to destroy any larvae, Keep the garden free of plant debris.

Leaves are somewhat curled, deformed, and-or discolored. Plant growth is stunted.

Leaves are yellowish and slightly curled with small shiny specks

Look for a sap-sucking insect. Aphids are the most common. Aphids are basically plant lice. They are Yellowish-pink to pale green, soft-bodied, oval~pear shaped insects and are commonly found on nearly all varieties of plants.

Hand picking is not feasible as they are too small and numerous, Hot Pepper Wax helps to repel aphids from your plants, but needs to be frequently re-applied.

Neem is the safest and surest eco-friendly mode of Aphid control and can be used in conjunction with predatory strategies such as Lady Bugs.

Plants are sheared off near the soil level.

Cutworms are the culprit. They gray to brown nocturnal grubs that feed at night. Handpicking grubs from the soil around plant bases is helpful, however, they hide in the soil by day and are not easily spotted. Keep the garden free of plant debris.

Bt – bacillus thuringiensis is a bacterium that is known to kill cutworms, and is readily available to home gardeners.

Leaves are curled upwards. Mature foliage turns yellow which progresses to brown. Purple margins on young leaves.

Potato psyllid could be the problem, it is a small light grayish green insect, somnetimes mistaken for an aphid. They inject a toxin into leaves while feeding which causes the symptoms described. They are rarely a major problem. The same controls used for aphids can be applied to the psyllid.