PapaGiorgio
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Posts: 5
Joined: Mon Sep 26, 2016 2:02 pm

White Spots on Lemon Tree Leaves

My girlfriend just bought a house with a lemon tree in the back yard.

The lemons are looking very dusky, with thick dry skin. I've included some pictures of the fruit and the leaves. Can anybody help?

Thanks!
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imafan26
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Posts: 13947
Joined: Tue Jan 01, 2013 8:32 am
Location: Hawaii, zone 12a 587 ft elev.

No one has taken care of that tree for a while. It has whiteflies. Possibly the dark spots may be some bacterial or fungal spot. The lemons are pale but it depends on the stage of growth and variety. Russetting may be from mites, they make the skin hard and dry but the fruit will still be edible. It can limit the size of the fruit since the skin is less pliable.

Clean up the tree and get rid of the whiteflies. Spray the tree weekly with insecticidal soap and use the jet setting on the sprayer to get under the leaves and blast off the eggs (white rings). You will have to do this repeatedly every week as insecticidal soap will get the crawlers but the adults will just flit away and come back later. Spray the tree with a strong jet of water under the leaves daily to keep the whiteflies from reestablishing. Annoy them enough they go away. This is how I keep them off my peppers.

Pick off the leaves with the brown spots; bag and trash. Clean up any debris under the tree. If the weather is cool enough, you can use orchard spray it contains sulphur for fungal disease and mites and pyrethrins (will take care of the whiteflies) Do not spray when the tree is in flower. Pyrethrins are toxic to bees.

Feed the tree with citrus food. I feed 2-3 times a year (my trees are 8-18 years old and I use a slow release fertilyzer + citrus food). Once just before the leaves flush and again after the fruit sets. Some citrus trees like the Tahitian limes only bear once a year, calamondin will set fruit multiple times a year and will bloom while fruiting so it needs more fertilizer. Meyer lemons will set fruit about 3 times a year. Younger trees will need to be fed more often.

Citrus trees like well drained soil. Deep water once or twice a week.

Citrus can only handle light pruning. Never cut back a citrus tree sharply or at the wrong time of the year or it may not fruit for a couple of years or until the canopy has recovered.

https://edis.ifas.ufl.edu/hs132
https://edis.ifas.ufl.edu/hs141

PapaGiorgio
Newly Registered
Posts: 5
Joined: Mon Sep 26, 2016 2:02 pm

Awesome. Thanks for the help!

gumbo2176
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Posts: 3065
Joined: Mon Jul 19, 2010 2:01 am
Location: New Orleans

I had a citrus tree that was killed when Katrina hit and one year I had issues with thick skinned, hard to peel fruit and it turned out I had Citrus Rust Mites. The fruit was good, just the skins looked off-color and very hard to peel. I used an oil spray several times over the year and especially when the trees were bearing fruit and that did the trick. The next season I had beautiful fruit with no blemishes.

Too bad it couldn't survive the almost 5 ft. of water that hung around my property for a couple weeks after the levees broke.



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