New to houseplants - what's wrong with my chilli plant?

Question

I'm currently growing a few chilli plants from seed in my apartment, but the largest one is having some problems. Some of the leaves are curling, whilst others have a dusty, salty substance on the bottom and light green patches on the top. Parts of the stem have started to brown. (Photo gallery here: https://i.sstatic.net/qqMjv.jpg)

As I'm really new to growing plants in general, I have no idea of the cause - I've been watering them fairly frequently recently (around once a day/once every two days) as they live in a sunny windowsill (well, for the UK) and the soil appears dry. None of the plants it lives alongside (also chilli plants) are having the same issues, though it is the largest of the plants and may possibly require repotting? I've spent a long while Googling, but haven't been able to find anything that matches the exact symptoms.

Any ideas?

Answer 1

I would say that it is almost certainly looks like the result of some aphid/mite attack. But, you say it is just on one of many plants, which is noteworthy.

If it was a water/re-potting need, you'd usually see other issues, like say, yellow leaves, one possible sign of water retention issues. Besides, looks like you have been watering them well.

I would set the plant aside, as far away from the others as possible, wipe down the residue and treat the plant with a diluted solution of soap and water, or an organic insecticide.

Observe the plant closely over the next few days and see what happens.

If you remember the type of breed/hybrid it is, you could look it up and see if this breed is particularly prone to any type of bugs or diseases.