Hello, I think there is definetly hope of saving the potatoes. That does not look like Early blight or lateblight to me (google potato early blight and potato late blight to see pictures). I'm guessing it is septoria leaf spot but I'm not sure. Septoria is a fungal disease of the potato/tomato family. Treating with a fungicide may not be required. Septoria is worse in tomatoes than potatoes. You may wnat to treat the tomatoes with a biweekly spray of 1 tbsp baking soda to 1 gallon water. Just make sure to test it on a single leaf first and then wait a day to make sure the leaf doesn't "burn".

Don't cut all the topgrowth back. If I'm right that it is septoria your tubers are safe and cuttig the plant back will just rob them of energy.

Eggplants are in the same family as tomatoes as are potatoes peppers petunias nightshade and others. The family is called solanaceae.

Wow. I haven't heard of Septoria before, but the pictures on Google look spot on. Actually, it looks like the same thing that hit a tomato and brugmansia last year... and a bit similar to what uglified a few mint plants. I'm almost tempted to say that an extra pot of soil, which probably had a sick-ish tomato from last year, was dumped in that part of the raise bed. I'm really hoping that any leftover leaves and whatnot did not introduce the Septoria to the garden. Nothing else around the potatoes are affected yet (peppers and tomatoes).

I'll give the baking soda mix a go on the tomatoes (and peppers?). Would vinegar and water work too? I only ask because I was told once to use it for fungal problems with seedlings but I never tried. Is there a particular fungicide you would suggest to combat the Septoria?

Thank you so much! I was close to chopping them down and tossing them in the chiminea.

Don't use vinegar in water. Vinegar is used as a herbicide. Although it is not particularly effective until much higher concentraions are used even the 5% stuff with burn back all the leaves on your plant. Baking soda in water works ok as a preventative it probably won't eliminate the septoria but should keep it under control. You can also try dusting your plants with normal powdered cinnamon as well as a host of commercial products.

Cinnamon... interesting. I'll spray some with baking soda and a couple with cinnamon. I'm curious to see how the cinnamon works. Should it be dusted on after watering, while the plant's surface is still moist? What about baking soda and cinnamon in a spray? Easy fungus prevention with a great scent!

The first picture says the plant ran short of water. Dry soil; windy weather; low humidity; and/or damaged roots -- you decide.

I thought it might be wind burn but that rarley results in spots. Cinnimon can be applied as a spray but it tends to clog the sprayer so I'd dust it on after you spray the plants. Just be sure to test the bking soda on one leaf first before spraying the whole plant.

The soil did get a bit dry a while back (clogged soaker hose), but there weren't any signs that the potatoes were thirsty at the time. It has been breezy the past couple of weeks too. I wouldn't be surprised if that's what caused them to weaken and yellow... and then get hit with Septoria. Ah well, I'll do the baking soda spray and follow with cinnamon to keep it from spreading, and then run out to get some Ortho or Daconil fungicide.

Thanks a bunch!