I noticed about 4 days ago that leaves on one of my peppers got soft and started to hang down a little. I thought that it just needs some water so i watered it along with my 2 other peppers. Today the same pepper looks like it again needs more water, while the other 2 are in pretty much good shape. I inspected the plant and found out that a lot of leaves from its top half are completely dry and basically dead. The rest of them is either normal (young and small leaves look the best) or seems to be attacked by an insect (or a disease?) i can't identify by myself.
I have also noticed one tiny white/yellow bug walking on the plant. I couldn't take a clear picture of it, because it was to small.
Are these symptoms caused by an insect or is it a disease?
If it is an insect, how can i get rid of it?
Are my other plants in danger?