It can be alarming to look over your potato patch and notice bright yellow spots mottling the leaves. While it may signal serious trouble yellowing potato foliage can have various causes. Read on to learn about the common reasons for yellow spotted potato leaves and what you can do about it.
Potato Virus Y
One of the most likely culprits behind yellow-speckled potato leaves is a virus – specifically Potato virus Y (PVY) This harmful and extremely contagious pathogen manifests through yellow mosaic patterns on the leaves
PVY spreads readily between plants via aphids. Once a potato plant is infected, there is no cure. The virus significantly impacts yield and potato quality. Preventing PVY infection is critical through vigilant insect control, weed removal and using certified disease-free seed potatoes.
Early Blight
Early blight fungus can also lead to yellow spots with dark brown borders on potato foliage. This fungal disease thrives in humid conditions. A telltale sign is the concentric ring pattern the spots form on leaves.
Prevent blight by avoiding overhead watering, increasing air circulation through wider plant spacing, and regular copper-based fungicide application. Ensure potato tubers are healthy when planting.
Nutrient Deficiencies
Lack of key nutrients can trigger yellowing in potato plants. Iron or magnesium deficiency typically causes interveinal yellowing starting on lower leaves. Nitrogen deficiency yellows the oldest leaves first. correcting nutrient issues requires a soil test to pinpoint what is lacking, then amending soil and fertilizing accordingly.
Herbicide Injury
Overspray or drift from lawn weedkillers containing 2,4-D or dicamba can injure nearby potato plants. Contact with the broadleaf herbicides causes yellow curling, cupping and crinkling of leaves. Avoid spraying these chemicals anywhere near vegetable gardens.
Environmental Stresses
Heat, drought, waterlogging, compaction and other environmental stresses can induce yellowing of potato foliage. Stress-related yellowing normally starts at the bottom leaves and progresses upward. Ease stress by mulching, improving drainage, consistent watering and shading plants on extremely hot days.
What to Do About Yellow Leaves
If you spot yellow leaves on potatoes, take these steps:
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Inspect leaves closely to note pattern, location and border colors of spots. This helps identify the cause.
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Check undersides of leaves for insects like aphids that could spread PVY.
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Feel leaf texture – crinkly leaves point to herbicide damage.
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Review recent weather for temperature spikes, heavy rains or drought that induces stress.
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Test soil moisture and drainage where discoloration occurs.
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Send plant samples to a lab for pathogen testing if an unknown issue persists.
While yellow speckled potato foliage is alarming, the cause may be manageable if promptly identified. Avoid planting potatoes again in affected soil for at least 3 years to reduce disease carryover. Disinfect tools after working around troubled plants. Prompt diagnosis and treatment can help minimize lasting impacts.
Preventing Yellow Spotted Leaves
An ounce of prevention is truly worth a pound of cure when it comes to problematic potato leaf spotting. Here are some proactive measures to avoid yellow speckling:
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Select certified disease-free seed potatoes from reputable sources
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Rotate potatoes to different beds each year to disrupt disease life cycles
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Control aphids and other sap-sucking insects that transmit viruses
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Weed the garden frequently to eliminate alternate viral and fungal hosts
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Space potatoes appropriately to encourage air flow and reduce humidity
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Use drip irrigation instead of sprinklers to keep foliage dry
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Applypreventative copper fungicide sprays every 7-10 days
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Check soil nutrients and pH annually and amend as needed
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Use resistant potato varieties like Defender, Elba, Jacqueline Lee and Missaukee
Staying vigilant for early symptoms at the first sign of yellowing provides the best odds of protecting your precious potato crop. Catching and addressing problems quickly can mean the difference between a healthy harvest, or complete crop failure. Don’t delay taking action if you spot those worrisome yellow leaf spots.
Corky Ring Spot Tobacco Rattle Virus
- The leaves may not show any signs or may have yellow rings, spots, and arcs on them.
- Stems may be mottled green and yellow
- Tubers get brown rings and arcs on their skin and inside their flesh.
- Cracks and misshapen potatoes can happen if infections start too early.
- More information on Corky Ring Spot
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Verticillium Wilt Verticillium spp.
- Leaves turn yellow then brown and wilted, stems remain erect
- Signs are usually only seen on one or a few stems, not the whole plant.
- Often only random plants scattered in the field are affected
- You can see brown rings or streaks just under the skin if you cut the stem close to the ground.
- If you cut the tuber flesh at the stem end, you can see dark brown to black rings or streaks.
- More information on managing plant diseases in the home garden
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Blight: 5 Ways to Control Potato Blight (Late Blight)
FAQ
How do you treat yellow potato leaves?
What are the spots on my potato leaves?
How to get rid of potato blight?
What does potato blight look like on leaves?
How to fix yellow leaves on potatoes?
You can fix the yellow leaves of potatoes by applying water and fertilizers adequately. In case of any disease or insect attack, immediately apply appropriate fungicide, bactericide, and insecticide treatments. In addition, making sure plants receive optimal light can also stop yellowing.
What are some of the negative effects of potatoes?
I would say that the potato itself does not have a negative side, it is another food option that we have and that has been part of our food and tradition for a long time. The problem is the way we use and prepare the potato. When we remove the husk, we already lose a good part of the nutrients and fiber. When we fry, we add a huge volume of fat and substances that are not good for our health. When we make a puree loaded with unhealthy ingredients, we lose the essential characteristic of the potato.
Why are my potatoes turning yellow?
Fusarium wilt and verticillium wilt are soil-borne diseases that cause yellowing of older leaves close to the ground, followed by the rest of the plant.Potato blight, characterized by browning leaves with
When do potato leaves turn yellow?
When you’re potato leaves turn yellow late in the growing season, it’s a safe bet they’re ready to harvest. Pull the first plant out of the ground, check the tubers, and if you’re happy harvest and store the rest. When potato plants are mature and ripe for harvesting, they will show this through yellow leaves.