Could it just be heat stress since they are along the edges where the soil is dark and not protected by the leaf cover? It looks like it is mulched good.

Larry,

I have a couple of thoughts on the yellowing leaves, but I don't know that I have any solutions to recommend.

Like Carol, I think it might be heat stress or drought stress. However, if you had several inches of rain in a fairly brief period recently, then it likely is something else--possibly fungal disease or maybe something bacterial, unless.....

Unless you planted them in a nematode infested area. In that case it might be nematode damage.

Another thing I can think of that might cause the yellowing foliage would be fusarium wilt, but if that is what it is you'll know pretty quickly. Usually it hits the plants one day and all you notice is yellowing leaves, and then within another day or two you see the yellowing leaves followed by wilting and plant death. There is not a cure once fusarium hits.
Generally I do not see diseases on sweet potatoes except following a period of very heavy rainfall, and then I'll see one of the rot diseases that causes the stems and/or leaves to turn black and rot.

If the plants looked bad when you planted them, then the best thing to do at that time would have been to dip them in a fungicide recommended for sweet potatoes. Sometimes that can prevent further fungal issues from developing.

Sorry, I feel like I'm not being very helpful. What I likely would do would be to gently dig in the soil near the most yellowed, most wilted plant and see if the soil is either excessively wet or excessively dry. I'd try to push back the soil from the crown of the plant where the foliage emergences from the ground and check for any sign of disease on the stems.

If Daconil still is labeled for use on sweet potatoes, you could try spraying the foliage of your plants, or you can use copper as long as the label doesn't warn against using it in excessively high temperatures. If the problem is a fugal disease, that likely would keep it from spreading from one plant to another. Sweet potatoes are prone to many diseases that cause leaf spotting and yellowing but I think they must be more common in humid areas because I just don't see them here in my area where it usually is hot and dry with relatively low humidity during sweet potato season.

George may have some ideas for you since his climate and weather in general are more like yours than mine are.

Finally, if you see this disease hit and then move up a row of plants, one after another, in a straight line, that would seem like it might be cotton root rot, which I had trouble with in Texas, and for the first couple of years here. Cotton root rot's name can be misleading because you don't have to have grown cotton in a specific area in order for your plants to get it. It is soil-borne and affects several thousand different plants. I think there's only a really slim, almost miniscule, chance it would be CRR though.

Dawn

I've been doing the Sweet Red Cucumber Rings, which use red dye. When I read the title of this post, I thought "why would anyone want to dye sweet potatoes? Their color is nice just like it is." Too much heat, I tell ya, too much heat.

Thanks, Ladies.

I doubt that it is heat stress because it is in only one spot. I am thinking some kind of disease or roundup damage. My wife goes at every thing like she is fighting fire, and she has sprayer around the garden and flower beds. I am happy that she wants things to look nice, but she is dangerous with a sprayer. I am leaning more toward a disease because the other areas she had nicked with the herbicide have just about healed now.

I think I will dig the plant and take pictures so others may see and guess what the problem may be. I still have one of last years potatoes I can plant back in that spot.
I doubt that it will produce but it will make the bed look better to have the mulch covered.

Larry.

Larry, is this the sweet potato you asked about starting late? If it is, it looks great.

bon

Well, I took a picture but I did not see anything that just jumped out at me. I did see some rot on the roots. I did see a little mold on one of the dead vines, but I would expect that on a plant that had been dying for a month or more.

Bon, I dont remember about asking about late sweet potatoes. I did however get some planting done late this year, but I think the sweet potatoes were planted earlier than normal because of the warm spring.

The soil in the bed looked good and I planted the last of my last years sprouts back in that same spot. If I have a disease in that spot I expect it will show up on the new sprouts.

I was happy that I still had 5 potatoes left from last year. Madge cut the end off the potatoes and I planted them

I wish I had more to report about the dying potatoes. I have replanted, will re-mulch and expect the foliage will fill in soon.

Thanks again for the help. Larry

Seedmama, Well, you know, some of those crazy Sooner football fans might want to have some red sweet potatoes for tailgating this autumn.

I think maybe you're getting too hot there in the kitchen while canning. : )

Larry, Is that a slow-draining area? I am thinking the recent rain and wet soil might have encouraged one of the rot diseases that sweet potatoes are prone to get in wet soil. My garden got hit by a sweet potato rot disease after heavy rain in about 2007 or 2008. It was my fault because I had put the sweet potatoes in amended clay. Since then I only put them in the sandy-silty soil near the pecan tree, though it now is getting too shady for them to do well there.

Dawn

Dawn, none of my soil drains well. You may have noticed that I have attempted to raise all of my growing areas sorta like a borderless raised bed, but their surface is only 3 or 4 inches above grade. The potato plant that rotted was in the lowest part of the bed, so you may be on to something about the rot and the rain. Also, that bed is a flower bed also and madge and I both may have been watering it.

Larry

Can't add anything here. Bet it could be some kind of rot. Beside that, if there is a chance of Round Up drift, it could have taken a hit from that. Though, I'd expect it to die more evenly from that.

George
Tahlequah, OK