chinese elm black spot?

watchndsky

Thanks - Im aware of 1-4 but I was afraid number 5 might a little much for the tree while it was weak.

I was afraid that full feedings might be too much for it, and was thinking smaller doses might be needed. So thats what I was doing.

Do you think I should resume the normal fertlization schedule?

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SiNguyen

Hi w. without seeing your tree it would be hard to say for sure. But in my experience, I rarely ever see a Chinese elm that is really really sick just because of the black fungus. So yes, if that's all that was wrong with it, then I would resume feeding. Keep at half dose for another month if you wish, that will be ok too.
Good luck, Si

Yandrosxx

I have had the same problem with my chinese elm for several years.

I cannot emphasis the following enough:

Do not water the foilage in the evening time. PERIOD.

Always water in the mornings. Watering in the morning has drastically reduced the recurrence of leaf spot on my elm. Leaf spot is also the only disease/pest I have ever had on it.

Safer's makes a three in one product with a fungicide in it in a concentrate formula. I spray my trees once a week regardless of their condition. It is a mild formula and have never had any problems from using it on any species.

Other than a small case early this season, I have been able to keep the leaf spot at bay and the elm is in great health and looking good.

If the foilage stays dry, which it should if you water in the mornings only, it is very unlikely you'll get recurrences of the fungus once under control. And when you do they are quickly correctible.

watchndsky

I think I may focus on the "preventative" part a little more. This was a first for me but it affected all of my elms.

I always water in the morning, they get lots of sun and if I dont the soil is way too dry by the time I get home due to our unseasonably hot and dry spring.

Im hoping this last tree bounces back ok without too much damage to the branches. Its a lovely tree with a fat gnarly old trunk, I'd really be sore if anything happened to it.

DrDirt

I still think there's someting else going on here. Look carefully at watchndsky's pictures. The black fungal spots occur on completely chlorotic leaves. Typically with a fungal disease we'd expect to see yellowing and necrosis in conjunction with infection, and localized to the infected portions of the leaf. Ergo, if a green leaf becomes infected, only the portion of the tissue that's attacked, and a margin around the leaf spot will yellow initially.

I'm not saying that there's no fungus present, but I don't think it's the primary cause of yellowing. My guess, either a micronutrient deficency or phytpothora root rot, or too much shade.

Watchindsky, are the fine roots dark colored and if so, can you easily pull the cortical layer (the sheath or skin of the root hair) off? leaving a fine white interior thread?

rockm

My guess would be too much water...

watchndsky

I would lean towards some lack of nutrients, I do think the the two biggest trees could stand to be repotted also. But I really dont see how I can be overwatering, Im pretty careful and the first sign of yellowing made me double check that anyway (i didnt notice the black spots at first it was the yellowing)

Most leaves that have yellowed or dropped all had the black scaley type spots on them, although there are some that started off with yellow spots.

I checked the roots again, pretty dry down there actually. The roots were all a lighter brown but I was able to pull the outer layer off leaving a fine white thread of root behind. No roots appeared dark or slimey etc. In the other tree (a larger zelkova) same thing, a little bit wetter, not quite as woody smelling and i did notice a couple of white roots that seemed to have come loose or something.

Also the trees are getting plenty of sun. Lots more than last year actualy when I had no problems.

Im still a bit inexperienced with root health so maybe Im missing something. What do you think?

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JayC

Hi watchndsky,

Sorry i'm not able to help you with this species. I have a single elm, bought earlier this year, that is starting to get a few yellow leaves itself (although it could be the time of the year). So no epxperience here.

Good luck with fixing the problem! Do you have any photos of the whole tree? I would love to see the "gnarly old trunk" for inspiration......

JayC

ALDEVAUX

The symptoms shown are definitely very typical of black spot which begin with yellow lesions followed by the black stromata that are shown very well on the leaves.
The leaves that turn yellow before having spots are most probably due to the infection of their petioles and limbs which are also quite susceptible to the fungus.
Of course, as suggested by SiNguyen, the tree would be more susceptible to the disease if it is weak by a lack of nutrients. A tree has to be very healthy to be resistant to the many different disease problems that can affect it.