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Monday, September 3, 2012

Young Apricot Leaves Drying Up and Liquid Oozing

Q. I planted a Blenheim Apricot in March.   At first it did not seem to take but within four weeks it began showing growth whereas all the other fruit trees took almost immediately.  Its been doing fine until just recently when I noticed some of the leaves on the main truck were drying up.   I check the moister level regularly.   Looking closer at the graft there seems to be some liquid oozing out.   Enclosed are some photos of the liquid, drying leaves, and tips of higher leaves.   Any thoughts on what I’m up against.   Rootstock is Citation Hybrid if that helps.
All my other fruit trees planted in the same general area are doing just great.

Iron chlorosis, inter veinal chlorosis, or yellowing
between the veins typical of new growth when iron
chlorosis is present
A. Some great shots and I would like to post them on my blog. Your photos tell a nice story I dont get to tell very often. But first lets look at the obvious and the is the discoloration of the leaves.
The yellowing between the veins is called "interveinal chlorosis". Chlorosis just means "yellowing" so it is yellowing between the veins. The most common reason for this in our alkaline soils is nutritional and frequently it is a lack of iron. Other nutrient deficiences that can cause similar types of chlorosis can include manganese and zinc deficiencies. I would guess this is an iron problem.

The picture of the sap at the place where the rootstock (in this case Citation) meets what we call the scion (in this case yours is Blenheim apricot) we see some damage. It is very close to the bud union or dogleg (where the two meet).

Bud union or dogleg. Where the Blenheim apricot was
budded or "grafted" on to Citation rootstock and sap
The damage may have started at the time of planting and is most likely from sun damage or sunburn. This area should have been painted with whitewash or any diluted white latex paint. Dilute 1:1 with water. Or you can put anything in front of that area that would give it some shade until the tree puts on some canopy and shades itself. You can use wooden shingles, cardboard, anything to cast a shade on the trunk.

Usually, if the trunk gets sunburn then it is highly likely it will also draw borers to the damage and you will get borer damage there. It is very likely this is what you are seeing. YOu can find out easily by bending the canopy of the tree over. If the trunk breaks, it will break at the borer damage and you will most likely see them there. If it does not break when you bend it, it may just be sunburn. If the sunburn is not extensive, it is posssible it could heal itself but rather unlikely. You may have lost the tree.

Interestingly, this dunburn and damage at the dogleg can also lead to the chlorosis or yellowing of the leaves as well. The sunburn damage can interrupt the flow of nutrients including iron up the tree and the interruption may be enough to limit the supply of available iron and lead toward iron chlorosis. However, some iron chelate sprays on the leaves a few times, along with a teaspoon of Ivory liquid per gallon of spray, may be enough to green the leaves up. I would guess 4 to 6 applications made in the wee hours of the morning when it is cool.

Next time whitewash the trunk at the time of planting or provide some shade on the trunk until the canopy gives enough shade to protect itself.

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