Q.Is my Kaffir lime tree being affected by some sort of leaf disease?
My kaffir lime tree is showing some rough, brown circular discolourations on both the top side and undersides of the leaves. As the tree is still young, I am unable to check the fruits to see if they have been affected as well. The plant is about 1 year old. I am wondering if my tree has been affected by any disease, and if so, how can I treat it?
From the photo, I am unable to zoom in to see the spots, but I can see extreme "chlorosis" (yellowing), indicating a severe nutrient deficiency. This can contribute to susceptibility to leaf fungal disease, which may be what the leaf spots are.
The first consideration is watering. If you water adequately, not too much and not too little, the soil nutrients can be taken up and utilized by the plant.
This article gives some tips on fertilizing citrus:
Here's an article on pesticides for citrus: