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I have a (thai) chili in my kitchen. It seems to be fine overall. One week ago I discovered some white spots on the bottom of the leaves (see image).

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Whatever it is it does not seem to be moving. It is also kind of hard to scrub off. I tried it with the fingers, that does not work very well.

Some leaves are more afflicted while others do not have this symptom. After a search I found this question. In this question the plant seems to have scale. While the white spots do remind of what my plant has, mine does not have any brown or dying spots on the leaves. It also seems that her/his plant has this on the top of the leaves too.

So I wonder is there any reason to be concerned? Can anybody confirm scale or anything else?

Update:

After some more research I discovered a condition named Chlorosis (Edema) which is caused by overwatering. I have to admit the photos I saw look a lot like what my plant has.

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The strange thing is that I did not have the impression that I am overwatering. I always wait until the soil is really, really dry. Might this also be caused by putting too much water at once?

Community
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チーズパン
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    I don't know what the disgnosis for your plant is, so I post this as a comment, not an answer. Chilis like a small quantity of water every day, as opposed to succulents and cacti that like large quantities of water at once, followed by draining and drought. – Alina Apr 10 '17 at 10:00
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    Edema isn't necessarily caused by watering, but humidity, warmer temperatures and crowding of plants can contribute. Spider mites might make some damage that contributes to the lumps in the leaves caused by edema. I'm not sure that what you have here is edema. It sounds like it, but it doesn't look exactly like the edema I've experienced on peppers. Getting leaves wet can contribute to edema, too. – Brōtsyorfuzthrāx Apr 12 '17 at 03:38
  • I just thought I'd chime in super late to the discussion because I've had what appears to be the same thing on one of my sweet potato starts. I'm wondering if it's trichomes? For me, it's just on two leaves of one plant, and I have a whole tray of plants next to each other under a grow light. [![enter image description here](https://i.stack.imgur.com/ws7tr.jpg)](https://i.stack.imgur.com/ws7tr.jpg) – Amy Apr 25 '19 at 17:05

3 Answers3

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As you've correctly surmised, this condition is caused by edema. Now, edema can be caused by overwatering, but it can also be caused by high relative humidity coupled with a lack of sunlight. In other words, if your plants aren't drying out quickly enough, they may suffer from edema.

Additionally, if the soil surrounding your plants lacks potassium and calcium, you should consider fertilizing it, as a lack of one or both nutrients may encourage edema.

See what happens if you use less water when hydrating your plants.

grill
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Same problem here, working on it. I have small pots, and the soil is getting bone dry every single day (it's very hot here) and the plants wilt slightly. This is when I water. So I don't think it's "overwatering" per se, but also has to do with the frequency of watering.

Right now I opened up the the door and all vents of my green house as much as I can, plus the fan blowing. Trying to save the plants. Had it very bad also last year.

George
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I read somewhere that the Black Pepper plant has salt or sugar crystals that form on the underside of the plant, and will eventually turn to dark spots on the leaves. It is my understanding that as the plants grows it releases these sugar/salts that it doesnt need as the plant expels moisture.

Zonri
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