Hi, I am new to this forum. I am growing citrus trees from seeds for 5 years now. I have around 50 trees in the living room. I have a problem with a 2 year old mandarine tree (or orange tree). It was on a shelving near the patio door with others. Suddenly it started to have yellow spots on the leaves and more underneath the leaves. I am wondering if it's a disease or a deficiency. Or is it just reacting to the changes in weather as we had 2 weeks of rain ? Anyway I isolate it and water it with hydrogen peroxide/water in case it is reacting to bugs ( I have some little flies in the house). Here is some pictures. Can you tell me what it is ?
the pattern doesn't quite match any nutrient deficiency I know about. Possibly a nitrogen deficiency, although that is usually more uniform yellow. It could also just be the citrus re-absorbing nutrients in preparation for a burst of growth.