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Desert Museum Palos Verde sick, matted leaves. Help!

Harbor City, CA

I purchased a 12 foot Desert Museum Palos Verde and planted it a year ago. I live in Los Angeles. It thrived last year and flowered until November. We had a wet winter and spring. I live a few miles from the coast and we have cool, damp, overcast weather every day till about noon throughout the spring and early summer. Then generally hot sunshine for the rest of the summer and fall. This spring the palo verde had a silvery white coating on most of it's leaves. I sprayed it with a copper fungicide and it looked a little better, but still silvery. It bloomed, but not like last year. Now the bloom has pretty much stopped and the leaves are less silver, but look matted and irregular, forming big clumps near small branches. The branches and trunk look green. I don't know what to do. Should I spray it every week with copper. I have two smaller Desert Museums in the back yard. They were very small when I planted last August. They also had the silvery stuff this spring but seem to have fought it off and are now growing great with nice bloom and nicely shaped leaves. They get a little more sun earlier in the day than the large one in the front yard that is struggling. Any help you could give me would be gratefully accepted. I don't want to lose this tree. I've attached some photos of the matted leaves. Thanks in advance for your help!

Thumbnail by PabLoLA Thumbnail by PabLoLA Thumbnail by PabLoLA
Pequannock, NJ(Zone 6b)

Not a tree or zone I'm experienced with but sounds like powdery mildew caused by your wet, cool spring conditions and proximity to the coast. Maybe your new tree had more trouble fighting it off because it is newly planted and maybe the variety is less resistant than your established trees. Same with the lower bloom. The buds could have been reduced by the powdery mildew but also, it could be putting more energy into establishing roots.
It is really hard to see any detail in your photos. I am guessing you are past the cool damp humid conditions that favor PM at least until fall. Are the new leaves infected? I wouldn't keep spraying myself but really can't judge for you. Did you ever notice PM on your old plants before you purchased this tree?

Harbor City, CA

I planted everything at the same time last spring. I removed lawn and installed pavers and planting areas. Almost everything got powdery mildew after this unusually wet Los Angeles winter and early spring. I had the big dessert museum PV in the front of the house and two babies in the back yard. All three got the white silvery stuff on their leaves. But as the sun came this summer, the two small ones recovered and seem to be thriving. The big one, though seems to be struggling. Although it bloomed and doesn´t look so silvery, any more, the leaves are all deformed and clumped together. It seems to have new growth but deformed. I'm tempted to spray with copper a few more times. I attached two more pictures, one of healthy leaves on the small trees which give an idea of how it should look, and the other of the sick tree. Thanks for you thoughts.

Thumbnail by PabLoLA Thumbnail by PabLoLA
Pequannock, NJ(Zone 6b)

Yes, I see what you mean. However, also consider, the leaves can become twisted and deformed from too much chemicals and fertilizers. I'm not saying it is but did you try to make up for the PM by fertilizing or over spraying? Just a thought. The plant will most likely recover next year from PM but copper does stay around in the soil.

Los Angeles, CA

Hey PabLoLA, you’re not alone out there with the Palo Verde problems. While trees in my neighborhood appeared to be flourishing mine looked sick, wrong color, few leaves, suck clumps. After about 7 lousy years of first less water, then more water, no sprays or fertilizers, we gave up and put in a new tree. Now, just a couple of months later, I can see the beginnings of the mildew and leaf loss. Im sorry this wasn’t a helpful post, but I felt you should know you weren’t the only one with the problem.

Northern California, CA(Zone 9b)

PabLoLA, I wonder if you had a bad spider mite infection which caused growths of witches broom.

I was reading this article which says "Spider mites are a pest that cause palo verde tree disease. When spider mites infest a palo verde tree, they cause witches' broom."
https://www.hunker.com/13428882/palo-verde-tree-diseases

Here are pictures of witches broom that look similar to your clumping leaves.
https://www.researchgate.net/figure/Phytoplasma-infected-Japanese-maple-exhibiting-witches-broom-symptoms-a-d-shortening_fig3_263122893

And another photo I found online of a witches broom.

Thumbnail by Kell
Pequannock, NJ(Zone 6b)

Yeah, those last pictures look like Witches Broom. See this article just published.

'First Report of an Emaravirus Associated with Witches’ Broom Disease and Eriophyid Mite Infestations of the Blue Palo Verde Tree in Arizona'

https://apsjournals.apsnet.org/doi/full/10.1094/PDIS-01-18-0124-PDN

Northern California, CA(Zone 9b)

Also I think mites can give the affected leaves a silver white look as you reported.
http://hesed.info/blog/red-spider-mites-damage.abp

Thumbnail by Kell

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