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This is our first year growing potatoes (no potatoes or cultivated nightshades have been grown in this soil for at least 2 years before). Central NY zone 4b/5a. The potato plants started out healthy, green, and thriving, but have since stopped growing. The leaves are curling and turning brown. (And there's some flea beetle type damage which I expected and I don't think is the main problem.)

What could be wrong with our potatoes? What should we do about it?

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Update 2022-08-21 We harvested the potato patch yesterday. The plant tops were totally withered and brown. The potato harvest itself looks pretty healthy and blight-free, which is great! enter image description here

2 Answers 2

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One of our two types of potato is completely done (and ready to harvest, made a decent crop) (same zone, a bit more East) already. It might just be that.

Depending on irrigation, it might also be water and/or heat stress related given the way this year has gone.

Our other variety (don't recall either one's name, at the moment) is starting die-off but not all dead yet.

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  • It sounds like our potatoes are acting about the same. We just didn't expect such an early die off. Our potato harvest looks fine - not too abundant but not shabby either.
    – Kilobyte
    Aug 21 at 14:36
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First of all, I think you should consider that at least some of the damages look likes the result of a period with drought.

If you are sure that is not the case, some of the deformations in the leaves suggests a fungus like potato blight (Phytophthora infestans)

If it is a fungus, then the potatoes is usually damaged too. Compare to the photo at this NSDU page, which also states

Positive identification of late blight can be made by microscopic examination of sporulating samples from infected leaves or tubers. Identification of nonsporulating samples and identification of late blight genotypes can be done by PCR. This service is available at NDSU.

Rapid tests are also available.

In case of blight the NSDU page has several advices for management. I will especially emphasize

  • Destroy all cull and volunteer potatoes.
  • Plant late blight-free seed tubers.
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    If it's blight, try mulching next time. Blight needs fungus (typically splashed up from bare soils in rain or watering) and liquid water (already there if splashed up.) Mulching prevents splashing infected soils onto the foliage surfaces. Watering by a means that does not wet the foliage (drip, soaker hose, etc.) restricts water availability on the foliage to rain events.
    – Ecnerwal
    Aug 8 at 23:46
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    I was worried it was blight, but the potato tubers look unmarred by fungus and I'm glad of that. Thank you so much for the tips on blight management! We have had quite a dry summer with near constant sun all July and we didn't irrigate the potatoes at all. I have a love/hate relationship with mulch - I keep trying to use it but then get slug/snail problems. Am glad to know it can help prevent blight. We hope to get drip irrigation set up in the future.
    – Kilobyte
    Aug 21 at 14:34

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