Can anyone diagnose this leaf spot on cleyera?

[andyslawncare]

Leaf spot on Cleyera. My book by Michael Dirr states only Cercospora fungus attacks Cleyera, though online is claimed that Entomosporium also infects the species.

I didn't take a photo, but it had been heavily pruned early this year by the homeowner. Foliage drop looks to be around 20-30%. This is a new pruning/landscape customer as of today, so I want to go to do service next week with an answer, as he is a good candidate for a nice install next year.

I wasn't able to take a good quality picture due to the shine on the leaf, so I scanned a few leaves. The under side is easier to see spots, though the spots are larger on the upper surface, no gray--only black with brown outer edge on the spots surface spots and no holes. I saw no indication of damage on the stems, only on leaves. The mid veign underneath has a red tint about 1/2-3/4'' long after the petiole. Its not a mold.

Any thoughts and technique to treat? I've been treating entomosporium culturally on indian hawthorne.

Any comments are appreciated.

Thanks for reading.

zone 7A

[dKoester]

I'd start by examining what caused the disease. I'd then fix that problem(If possible) to prevent it from happening again, then treat.

[andyslawncare]

Originally Posted by dKoester

I'd start by examining what caused the disease. I'd then fix that problem(If possible) to prevent it from happening again, then treat.

In my experience, I agree for contracted maintenance accounts (since I'm guaranteed to continue to view a plant all year), but for added protection for future work I really want to know now to help expedite future deals and trust with the customer.

He doesn't have problems with the other areas of his cleyera, just this 1 hedge that is 6' tall and about 25' long--he has 2 others like this, and a yellowing azalea--I suggested that maybe his ph is too high, and should be checked already. I saw signs of chlorosis on a savannah holly near by. Possibly I'll just suggest a soil test again. before trying to conclude. Usually diseased plants have soil imperfection too, and they loose their guard.

[Smallaxe]

Black Spot, Brown Spot, Leaf Rot or whatever else you want to call it,,, I would look at the reason for slow growing leaves and old branches, anaerobic soil conditions with old tired , less than enthusiastic roots... Gardeners spend a lot of time with their soil constantly improving the tilth...

Once you are satisfied that the tilth of the soil is adequate, then look at sun/shade and air circulation issues... What I do in my own garden when it is going to be a dry sunny day,,, I'll hose off the leaves allowing them to soak in water early in the day strenthen their defenses against the microbes that are having lunch on your bushes...

I agree with dKoester, in that you discover environmental/cultural cause then treat...

[agrostis]

Man, cleyera are as bad as red tip's for getting black spot. IMO, your never going to beat it, it's a waste of time and money to try. I would get rid of those thing's.

[Think Green]

Interesting......as I replace red tips with cleyera's, Just as I replace common hybrid tea and grandiflora roses with knockout varieties.
This disease is supposed to be resistant in these two species of plant but nothing is to say it will not occur. My knockout roses sustained black spot and one plant exuded what appeared as the common mosaic virus. We are under the impression that these hybrids are immune to an extent.
Excessive moisture, humidity, foliar watering, and other host plant infections will spread this disease. Cool episodes with sudden changes in temperature is going to prolong this disease.
The best thing to do is definitely diagnose this disease from state testing. The guessing game isn't going to be accurate. Send in green leaf tissue along with stems. This way, the agent can diagnose the problem using a microscope. Many of us has seen diseases that appear to be similar, but no one is completely accurate without seeing the infection firsthand.