Over watered, underwatered, or fungal infection? Japanese maple

[vikaviolin]

I have a baby Japanese Ryusen maple and I started to notice the new leaves at the end of this one branch are turning black and dying. The rest of the leaves on the tree are green and healthy, just the ones at the end of this branch look not as healthy... It's been pretty hot here and the tree does have exposure to full sun in the afternoon. I don't know if it's leaf scorch, underwatering or possible a fungal disease...Does anyone know what the problem could be? Thank you so much!!!

 

[99 Mile Creek]

Do you have any photos of the entire tree? You may get more insight and a more accurate diagnosis from other members that way. As well as any info on the tree, e.g., how long it's been in your care, last time pruned, wired, repotted, other trees near this one.

However, it could be a fungus. A few that present themselves black are verticillium wilt and pseudomonas syringae, typically the latter working its way from the outside (foliage) toward the trunk.
If you diagnose it with a fungal infection, you can look into a fairly inexpensive H2O2 (hydrogen peroxide) treatment/spray/soak.

Good luck.

 

[Shibui]

Above ground symptoms of over watering and underwatering are very similar. The only way to decide is to check roots or know the watering history of the tree. Has it been dry over the past few weeks? Has it been constantly soggy for the past month or more?

Older leaves still Ok and stems still standing up points more toward fungal infection.

The older leaves are quite yellow between leaf veins. That's probably what we call chlorosis. Can be caused by nutrient deficiency or by alkaline soil which is often caused by high pH tap water.
The stress from nutrient deficiency could be making the tree more susceptible to fungal infection.

I'd treat for fungal infection but also use Chelated iron for a quick fix for the chlorosis. Acid fertiliser helps to counteract alkaline tap water longer term.

 

[vikaviolin]

Do you have any photos of the entire tree? You may get more insight and a more accurate diagnosis from other members that way. As well as any info on the tree, e.g., how long it's been in your care, last time pruned, wired, repotted, other trees near this one.

However, it could be a fungus. A few that present themselves black are verticillium wilt and pseudomonas syringae, typically the latter working its way from the outside (foliage) toward the trunk.
If you diagnose it with a fungal infection, you can look into a fairly inexpensive H2O2 (hydrogen peroxide) treatment/spray/soak.

Good luck.

thanks so much for your reply! Here are the photos of the entire tree! I've only had the tree for about 3 months and haven't pruned anything yet since planting it.

 

[vikaviolin]

Above ground symptoms of over watering and underwatering are very similar. The only way to decide is to check roots or know the watering history of the tree. Has it been dry over the past few weeks? Has it been constantly soggy for the past month or more?

Older leaves still Ok and stems still standing up points more toward fungal infection.

The older leaves are quite yellow between leaf veins. That's probably what we call chlorosis. Can be caused by nutrient deficiency or by alkaline soil which is often caused by high pH tap water.
The stress from nutrient deficiency could be making the tree more susceptible to fungal infection.

I'd treat for fungal infection but also use Chelated iron for a quick fix for the chlorosis. Acid fertiliser helps to counteract alkaline tap water longer term.

Thank you so much for your help! Do you know if each fungal infection has its own specific treatment or something general I can use? Would I also be treating the soil or the leaves with this? Thank you!

 

[99 Mile Creek]

View attachment 603225View attachment 603226thanks so much for your reply! Here are the photos of the entire tree! I've only had the tree for about 3 months and haven't pruned anything yet since planting it.

That looks really quite healthy. I'm not sure what I would do other than just keep an eye on it for now, hitting it with some h2O2, and ensuring it doesn't get any worse. It very well may just be typical dieback isolated to the one section.

If it becomes worse, you may want to consider taking off an inch or so below the infected areas with sanitized shears, making sure to sanitize them after/before making any other cuts. But that would be if it worsened.

I would just keep an eye on it along with the good advice above. Looks good though.