Author Topic: Mandarin tree with yellow leaves  (Read 1120 times)

dmitrig01

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Mandarin tree with yellow leaves
« on: January 04, 2020, 12:11:05 PM »
Hi! Thanks all for the wealth of information on this forum – I've learned a ton by reading the many great topics here. Now it's time for me to ask a question of my own :-)

I moved into a new place recently, with several beautiful citrus trees. One is a beautiful mandarin tree (not exactly sure which type), but some of its leaves are yellow. I've fertilized it with a high-nitrogen fertilizer twice in the past six months thinking that maybe that would fix this problem, and it definitely has improved a bit, but some of the leaves are still looking funky. I'm wondering if something else might be the problem.

Entire tree (looks like someone previously trimmed it into being a neat rectangle):



Leaves closeup:



Bomand

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Re: Mandarin tree with yellow leaves
« Reply #1 on: January 04, 2020, 02:01:14 PM »
I might try a little epsome salt or fish emulsion once in a while. Be aware that citrus constantly sheds leaves. The leaves last about 18 months. They start to yellow and finally fall off. This is the life if citrus leaves. Yellow leaves do not always indicate a problem.

Ilya11

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Re: Mandarin tree with yellow leaves
« Reply #2 on: January 04, 2020, 02:16:10 PM »
For me  it has a sun/heat damage.
Best regards,
                       Ilya

Millet

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Re: Mandarin tree with yellow leaves
« Reply #3 on: January 04, 2020, 02:41:09 PM »
Your trees symptoms are a little strange.  Looking at your pictures for some time I don't think it is a nitrogen problem,.  The symptoms for a nitrogen deficiency are:....Totally yellow leaves with no variation of color, or yellow/orange veins with some green out on the far sides.   A nitrogen deficiency is a mobile deficiency, meaning that the deficiency shows up on the older leaves of the tree with the newer leaves still retaining some green.  This is because the tree removes the nitrogen from the older leaves to supply the nitrogen to the new growth. Most of your tree's leaves show a yellowing on the new growth.  As you are in the Bay area, and it now January, I really would not think that the weather has been all that hot to cause sun damage, it not like you lived inland in the desert. The leaf symptoms don't seem to be correct for a magnesium deficiency either. I know there has been more and more Citrus Greening in California, especially in the southern part of the state,  Have you heard of it showing up in your area?  You can always call the county Ag Agent and ask for a person familiar with citrus  to come out an look at the tree. Normally this is done at no cost, or a very slight cost.   Foliar nutrient spray are 8 to 20 times faster clearing up a deficiency (if it is indeed a deficiency).  You could spray the tree with a fertilizer solution containing all the micro nutrients.  If you decide to do this, the best time to spray is in the morning on a cloudy day with relatively higher humidity.  Add a teaspoon of a surfactant per gallon of the nutrient solution.  The best to you and this tree.  I would be very interested in hearing further about this tree, and what steps you take.
« Last Edit: January 04, 2020, 03:15:28 PM by Millet »

Laaz

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Re: Mandarin tree with yellow leaves
« Reply #4 on: January 04, 2020, 05:18:11 PM »
Looking at the tree to the right which is already dead & the small tree to the left which looks like it has the same type leaf symptoms, I would assume some type of disease or soil issue.

dmitrig01

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Re: Mandarin tree with yellow leaves
« Reply #5 on: January 04, 2020, 05:29:44 PM »
Thanks so much for the speedy replies. I found this website online - https://www.yara.us/crop-nutrition/citrus/nutrient-deficiencies/magnesium-deficiency-on-lemon-citrus/ - which looks pretty helpful. One thing I forgot to mention earlier, is that the tree has dropped quite a few fruit in the past two weeks or so. When they dropped, the skin was green, although now it has turned yellow/orange on the ground. Here is a picture of one inside:



This makes me think that perhaps it's phosphorous deficient?

The rind is definitely very thick as well – not sure if it's because of whatever's going on, or just the fruit of this tree. I've never seen it have ripe fruit yet.

Here is a picture of a tree about 8 feet away (next to the small one in the very first picture):



This one seems to have its own problems, namely way too few leaves, but one thing that's notable on this one is that zooming into the leaves, I can definitely see a "V" shape that seems to be characteristic of magnesium deficiency.

(PS: tree to the left is an apricot, dormant for the winter)

dmitrig01

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Re: Mandarin tree with yellow leaves
« Reply #6 on: January 04, 2020, 05:30:14 PM »
Sorry, meant to say the apricot is to the right

Millet

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Re: Mandarin tree with yellow leaves
« Reply #7 on: January 04, 2020, 06:22:29 PM »
Your last picture does look like a magnesium deficiency. The leaves have the classic green delta shape in the center of the leaf, with yellow out to the sides.  However, I can see that these trees have not been taken care of for quite some time.  They need a good nutrition program.  For large trees 5 years and  older, they should be fertilized 3 times a year. Early spring, June and late August.  Young citrus trees 4 times a year equally divided between March 1 and end of August.