I have some indoor plants which have white and black spots appearing on the leaves. I'm not sure what the cause is, does anyone know what this is? The photo is of a chilli plant that has recently started to show signs of it. The leaves first become speckled with light coloured spots then it progresses to this black spotty area that you can see in the photo. I previously had a mini sunflower plant and a marigold which both died from whatever this is. I'm still fairly new to gardening but I haven't come across this problem before. Thanks for any advice you can give me!

It might be mildew, caused by humidity and stagnant air. The best cure is air movement between the plants. Still air and crowded conditions cause a lot of problems for indoor plants.

Have you seen any fine webbing around your plants? I'm wondering if it could be Spider Mite damage? Photos for comparison: https://www.bing.com/images/se...