Hey guys, can you tell me what on earth is covering my purple sweet potato plant? It is around lots of other plants and the weird thing doesn't seem to be interested in any other plants at all! And it's also only on the veins of the sweet potato plant...
I don't know what it is, but I've seen it before on sweet potato leaves, and I don't think it's a pest. Possibly edema? (I was sort of hoping someone else would jump in on this question, because I've been wondering about it for almost four years now.) E: so of course togata57 posts right at the same time I do. I don't think it was scale; the spots were hard and didn't squish like scale.
You said that already. And I agree! It did in fact visually resemble scale. It did not, however, behave like scale in any other respect: 1) there was no scale elsewhere in the greenhouse, before or after this began, 2) once on the sweet potatoes, it did not spread to other plant species, 3) treatment with pesticides changed nothing, 4) the individual flecks were hard, and couldn't be crushed by bare fingers (When crushed with objects, they turned to powder.), 5) the spots did not easily wipe off of the leaves, and when pulled off they sometimes took bits of leaf with them.
Thought that we were attempting to ID Insectivore's invader. Fascinating to hear of your experience, mrsub, but fail to understand its pertinence to the problem under scrutiny. I have had scale on my anthuriums that appears to be similar, if not identical, in color and leaf-vein-following to that displayed in Insectivore's photo. These laugh at pesticides and maintain a firm grip on the leaf. And there are multiple spp. of scale, which I will recklessly say probably vary in hardness and (in)destructability. Seems to me that more input from the poster is needed. So, Insectivore---is this infestation squishable (moist) or crushable (dry)? Have you noted the presence of sticky gackly substance around and about the leaves?
I will check them specifically when I get home. But I know what scale is....I thought. It is not interested in other plants at all like scale is, even in the plants that are in the same pot. It is on the top instead of the bottom, I know scale does not have to be on the bottom of the leaf, but it prefers it, right? It's really driving me crazy! It does not seem to be causing damage so far....I am worried about when the damage begins to show. I have used what I usually would use on scale (brought a plant to my house with it recently - again not the same as this - and had it in quarantine and treated it with alcohol spray) and it had no effect on this junk! And it’s white. It seems to be a sweet potato problem to me. I have tons of plants around it and it has not bothered them at all!! When I get home, I will check the solidness and “gooiness” (who knows how that should be spelled!?! Lol.) and get back to you guys.
It's appeared at roughly the same time of year, on the same species of plant, and follows the leaf veins in a similar way. In close-up, the picture of Insectivore's whatever-it-is appears clumpy and irregular, in the same way as the whatever-it-is on my picture, but different from the usual species of scale that affect indoor plants. (Some of the bits appear to be tall enough to cast shadows, in the photo, though admittedly the photo is blurry.) It's not "interested" in spreading to other plants, according to the original post, which is also how my thing behaved and which is not at all like scale would typically behave. Therefore, pertinence. I have resorted to googling "edema ipomoea," and based on what I found there, I think this is either a very unusual case of scale, or a bog-standard case of edema.
Please eliminate irrelevant and inaccurate allusions to my fictional omnipotence from your posts. Your actions are your own choice: I am not 'making' you do anything. Ditto for comments on my motives, as well. Hard as this may be to believe, I was oblivious to your presence on this thread until you drew my attention to it.
............mrsubjunctive........ What is edema? How do you suggest I get rid of it. The spots are tall enough to cast shadows. Sorry about the blurry picture, it was the best one I had. I cannot find it on my plant now. I was trying to trim all the leaves off that it infested but it seemed not to matter but recently I trimmed it way back. So, there are no present samples to check. Sorry I started a fight. I'm not sure what to do now.....
Insectivore, you are blameless. Mrsub and I have conversed, and all is well. Edema is swelling caused by water retention. See below: http://www.hort.uconn.edu/ipm/greenhs/htms/edema.htm
