Leaf Problems on Chilli Peppers
The attached photo shows a leaf from a Suttons Vampire Chilli plant, no markings on the top of the leaf.
The plants are indoors and are generally growing well and flowering. I have three of these plants all showing the same markings, they slowly increase across the leaf and also appears to be transferring to another nearby chilli plant.
The plants are checked daily and misted every morning, they are growing in a reservoir system so watering is constant with and wick for take up of feed, but the developing aqua roots will be doing most of the work I guess.
Each plant is given a gentle shake each day but I have never noticed any bugs flying off the plant, no visible signs of insects on top of the pot. I can not find anything that looks like this in my RHS Pest and Diseases book and people asked so far do not know what it is.
I would be very grateful for any advice you can give me and what action I should take.
From your picture it looks to me like Odema (also known as dropsy or intumescence), a condition caused by over-watering and / or too higher humidity. The excess water within the plant induces extra cell growth on areas in the leaves (can also appear on stems) and results in the warts / blisters you can see.
The solution should be to reduce watering, and increase ventilation. Maybe try stop misting every morning first.
Hope this puts your mind at rest, and many thanks for your query.
Pest Control Expert