Started sweet potatoes a while ago under grow lights. The potato rotted (like EVERYTHING ELSE SEEMS TO)…but I rooted slips and they’re growing well.
However, there is some kind of weird dot on a couple leaves. See top photo. Any ideas?
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I have seen this on my sweet potatoes. Do not know what causes it, but it doesn’t cause troubles later on.
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I also have this on some of my slip leaves but do not know what it is.
Just check my on my slips. I’ve gathered 3 different Asian types to try out in the high tunnel this year. 2 I’ve tried before (satsuma Japanese, and purple Californian type), but the russet skin yellow fleshed Korean type I found at an international market last fall is new to me.
2 issues I’ve noticed:
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All of the sweet potatoes had mealybugs. Interesting since I bought them all at different stores. The mealybugs seem to emerge from crevices in the skin. They did not appear to spread from one to another. I have to assume then that mealybugs are common on store bought sweet potatoes. Anybody else noticed this?
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I have the same (seemingly) mysterious dotting of the leaf surface. At first it almost seemed to resemble aphids or something but on closer inspection appears to be sort of crystalline exudate from the stomata. It’s on the leaves and petioles of only one variety- satsuma (common Japanese red skin/white flesh type). Wondering if anyone knows any more? I do see some leaf dieback along with it. Not sure which is the cause and which the effect though.
This is common with sweet potato slips/cuttings under indoor grow lights—sometimes other plant species, too. It’s a result of plant edema—the plant is taking in more water than it can effectively transpire under indoors conditions, and it’s causing cellular rupture and sap leakage: in brief, it’s something like a plant version of lymphorrhoea.
After the plants get acclimated to outdoors conditions, with better light and air circulation, they ought to put on healthy growth and do okay.
Some sweet potato varieties have more problems with edema than others. “Georgia Jet” seems resistant to the condition, and “Korean Gold” slips seem to have slight-to-moderate susceptibility when cultivated indoors. “Covington,” on the other hand, had a lot of edema problems in my grow room this year. In very severe cases where the edemic leakage extended to the stems (a minority, thankfully, of the Covington slips) the slips finally failed and rotted.
Will try to keep humidity lower and circulation better (more fans) in grow room next season. That ought to help some.
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