What happened to my Potatoes??

[strawhouse]

All my potato plants started turning dry, and brown and black at the tops, then the entire plant died off, it looked like I planted nothing in my potato patch. When I dug them up, the skin was all funny. And they didn't produce much, considering the plants died. Any idea what happened? I'm assuming I can still eat them, I fed them to my husband and nothing happened.
Bug or disease? I noticed a few weeks later the same thing started happening to half of my carrots. Browned, shrivelled up, and died. Carrots are really tiny, but look fine.
Thanks for the help guys!

[Vickie44]

I think that is scab , effected by the PH in the soil.

[geo in mi]

http://vegetablemdonline.ppath.corne...otato_Scab.htm

Scab.....see link

Your potatoes died down because they were mature--they reached their life span....not any problem.....

geo

[strawhouse]

hhmmm, certainly looks like scab!
But my plants definitely didn't die becasue they were mature. It happened early, and resulted in smaller potatoes and a small amount of them.
It started at one end, and eventually got to the other end, then migrated to my carrots. Which also died off completely. Wish I had pics of when it happened, but it's been a busy summer and I'm just now getting around to posting about it.
Any ideas what killed the carrots?

[Paquebot]

That's common scab. You're stuck with it forever unless you can move to a new field about a KM upwind. But then, if you're a KM downwind from scab, you'll get it anyway. All you can do is acidify the soil or create an acidic medium for the tubers to develop in. That can be done by using a 50/50 mix of soil and shredded fresh pine needles for anything above the seed pieces.

Carrots and common scab do go together and confirms that you have a bad case there. Since you can't plant them in infected soil and have them develop in a non-infected medium, it calls for drastically changing the soil. Semi-permanent way would be sulfur added according to what a pH soil test would call for. That would be good for a few years. For a one-season deal, same thing as potatoes but not 50/50. I'd go with at least an inch of fine-shredded fresh pine needles tilled in. The effectiveness only lasts one season and has to be renewed annually.

Finally, NO fresh manures from any source but rather well-composted only. They are alkaline and that's what common scab thrives on.

Martin

[geo in mi]

The scab, and the dieoff, are probably not related. If indeed, it came unusually early, I would consider alternaria--but that would be only remote, as the potato alternaria(early blight) and carrot alternaria are two different types of the same pathogen.....but conditions favoring growth would be the same. Otherwise, you might consider two seperate causes, but unrelated to the scab that you found.

There are other ways to outwit potato scab--one is by choosing resistant varieties. What you show in the picture looks like(I'm guessing, obviously) a Red Pontiac--known to be susceptible. Here's a link which gives some pretty good advice(though it is a pop piece) and some varieties common to Canada, that you might want to try. Also, the advice on consistent watering during tuber development is generally thought of as another good way to help prevent scab. http://www.albertahomegardening.com/...free-potatoes/

Another way shown down in that article's links, is to grow them in a layer of straw. This would be like Martin's technique of growing them in a layer of shredded pine limbs to make a blanket of acid conditions for the growing tubers, but the straw would be inert instead of acid. You could try either way...... In any case, I would suggest doing a pH test on the soil before doing too much ammending to create acidity chemically.....

Hope this will help.

geo

[Paquebot]

Downside to using straw as a tuber medium is that there may be few potatoes to harvest. Doesn't work well around here. Voles would use it as their condominium and cafeteria.

Martin

[jwal10]

Dad alway put sulfur on when he cut the seed and let them sit for a day before planting, never saw scab though....James