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Wednesday, November 21, 2012

Yellowing of Apricot Leaves and Possible Causes and Cures




Q. I have an Apricot tree I planted in January (bareroot from the farm).  It has been doing really well until a couple of week ago I noticed something was eating some of the leaves.  More recently I have noticed yellowing of some of the leaves.  Any ideas as to what is causing this and how to remedy the problem?  I have attached pictures.  Thanks.
 
Typical of iron chlorosis is that the newest leaves will have a lighter green leaf than older leaves AND the veins remain a dark green compared to the leaf itself. (Newer leaves are farther out on the limb than older leaves).
A. Photos 2, 3 and 4 looked like a nutrient or watering problem. The leaf or leaves were light green with some scorching around the edges. There might also be some wind damage. In photo it looks like a critter could have been eating the leaves but that is no big deal if it only affects a few leaves and doesn’t bother the fruit. In the photos 2 – 4 it does appear to be a nutrient problem.
 
Not a clear picture from the reader but you can see the scorching of the leaves on apricot.

See how the leaves on the ends of the branch are yellowing more than the older leaves coming from the thicker part of the branch? This is a good indicator it is most likely an iron or irrigation problem. Irrigation, too much, can also mimic iron shortages or actually cause an iron shortage. This is what you need to do. If there is mulch, pull the mulch away from the trunk. If there is no mulch, then pull the soil away from the trunk until you start to see the roots that were in the original container. I am concerned you might be developing collar rot. Planting the tree a little too deep can also cause similar looking problems.

Again not the best picture but it does look like an insect could have taken a chunk out of the leaf but chances are, if there were strong winds recently, it was wind damage.

If you are on a watering pattern that is every day, try to get off of it. Go at least every other day or even best every third day in the summer but add enough water to get the water down at least 12 inches into the soil. If it is hard to do this, build a donut around this young tree at least 18 inches from the trunk. Two feet from the trunk is even better.

One of the many iron sprays. Just make sure you adjust
the chemistry of the water to be on the acidic side so that
the iron is not lost when you mix it with water. To be
on the safe side I would use distilled or RO water
and use it all up. Don't keep it premixed for any length
of time.
This donut or moat should be high enough to hold about three to four inches of water. Fill it twice until the next watering. Because we are now in July, spray the leaves early in the morning with an iron fertilizer spray. Pick an iron product made for correcting iron chlorosis, an iron chelate is best. I usually recommend EDDHA iron but that is for applying to the soil. It is expensive and you do not need this chelate for spraying on the leaves.

Any iron spray made for applying iron to the leaves should work fine. However, some plants, in fact many plant leaves will not turn green from an iron spray without multiple applications. So I would make a fresh spray of iron for the leaves about four times and apply the iron on four separate applications a few days apart. Remember to apply it in the cool of the morning.

I would use distilled water or RO water. I would also put a tsp of liquid dish detergent (one with no addatives like scents or lotions) in one gallon of spray mix. Shake it to mix the spray and detergent together but not allow it to foam. Spray immediately.  Do not hold it overnight. Make a fresh spray each time you spray. Next January make your normal fertilizer application to the tree and include an iron chelate to the soil that contains EDDHA chelate.

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