Hi this is my young kingston pride tree ive grown from seed. as of recent the leaves have started looking sick, im not sure if this is, fungus, pest damage, cold damage, fertilizer burn, salt build up in soil? or is it taking the nutrients for new growth? it has started branching .. 2 branches have grown about 4cm with some decent size leaves over the last 3 weeks.. could it be taking the nutrients from older leaves? the weather here has been cool lately dropping to about 7c at night.. i have also had some little black bugs in the soil and on the leaves... which i have sprayed with neem oil.. but there is plenty stuck dead to the leaves that i keep wiping off... any idea?