Our young orange tree (planted in the spring) has been healthy but growing slowly. I’ve noticed light blue spots on the leaves (EDIT: upon a second look, I realized that the spots are really white, with a very slight bluish tinge), as if it had been sprinkled with kool-aid and it evaporated, but otherwise it seemed to be doing well so I ignored it.

We recently fertilized all of our fruit trees with citrus tree fertilizer, and they all perked up except for the orange tree. Its leaves are starting to yellow.

Any ideas on what is going on or how I can help it? I live on the east coast of Florida.

Orange tree

Orange tree closeup

  • Welcome Jim Clay! Thanks for adding us to your network sites! Would you please post some pictures of your tree, including the whole thing and close-ups of areas that are having trouble? Thanks! Dec 2, 2018 at 17:29
  • @Sue Thank you. I have added the pictures as requested, and I realized while doing it that the "residue" is really white, with a very slight bluish tinge.
    – Jim Clay
    Dec 2, 2018 at 21:17
  • Thanks for the detailed edit and great pictures! Unfortunately, I'm not an expert on these things, but we have plenty of people who are. I hope someone comes along quickly and helps you out! Dec 2, 2018 at 21:22

1 Answer 1


It can sometimes be hard to pin these things down to one specific cause. So lets just assume there are multiple problems and arrange some treatment.

White Mildew: Powdery mildew can be treated with regular applications of a fungicide such as neem oil, sulfur or triforine. Purchase a product and follow the treatment regiments on the product's labeling.

Leaf Curl: There are four major reasons for leaf curl in orange trees: pests, disease, water stress and weather. Sometimes it’s a combination of all four. Get a hold of some copper fungal spray and follow the treatment regiments on the product's labeling.

Over/under watered?

This is hard to say. It depends on: your climate, your tree's age, soil type and tree type. In general you should follow the regiment suggested to you by the person who sold you the tree and be observant, that being said:

Signs of Underwatering Trees:

Wilted or curling leaves that turn brown at the tips or edge. A sparse canopy of off-colored and undersized leaves. The leaves may be yellowing; tends to look like its in a transition period from summer to fall when its underwatered.

Signs of Overwatering Trees: (This could be you)

The ground around the base of the tree is constantly wet and new growth tends to wither. Leaves tend to seem fragile and will peal from the stock easily. As I said this could be you (mildew problems) slighting decrease your watering regime.

  • @Jim Clay Sure, no problem, GL!
    – Rob
    Dec 4, 2018 at 22:50
  • @Jim Clay If this answer is acceptable feel free to hit the accept button!
    – Rob
    Dec 6, 2018 at 21:18

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