[Help] Possible Fungal Issue with Japanese Maples

[JoeR]

I noticed these white 'spots/stripes' on a few of my maples some time ago but did not think much of it at the time. Now, I am concerned that it is some sort of fungi and I would like to get rid of it. It causes slight leaf distortion on new growth.



Anyway: what is this, and what should I use to get rid of it? Preferably something I don't need a hazmat suit to use.


Thanks,
Joe

 

[JudyB]

SCALE. You can find some insect sprays that can help with scale infestations, but they can be problematic and keep cropping up. Best case, spray then be vigilant and scape each one off, or use Qtips with rubbing alcohol to paint them with.

 

[JoeR]

SCALE. You can find some insect sprays that can help with scale infestations, but they can be problematic and keep cropping up. Best case, spray then be vigilant and scape each one off, or use Qtips with rubbing alcohol to paint them with.

Thanks for the reply Judy!

It doesnt look at all like insects, is there a way I can test to make sure its scale?

 

[JoeR]

Edit: after looking up pictures, it does look like scale. Will neem oil take care of them?

 

[0soyoung]

is there a way I can test to make sure its scale?

use Qtips with rubbing alcohol

 

[JudyB]

Do make sure you check all the rest of your trees for these, they can be quite an infestation if they get a foothold. They do seem to have an affinity for certain trees, JM's and fukien tea are some of their favorites!

 

[Stan Kengai]

Edit: after looking up pictures, it does look like scale. Will neem oil take care of them?

The neem oils may take care of both the scale and the tree. Japanese maples are sensitive to petroleum based horticultural oils, but I'm not sure about Neem.

 

[Nybonsai12]

do the white spots rub off with your finger? this looks really small for scale.

 

[coh]

Yeah, I'm not sure that is scale. Could be (or could be some scale along with another issue), so I would try to scrape some off. If it is scale, a systemic might be a good approach (bayer if you can get it, but there are others). Are there any on the softer, newer growth or leaves, that's where I usually find scale congregating...not so much on older stems/trunks.

For what it's worth, I've not yet had scale on any of my maples. They love figs and many other tropicals, though.

 

[JoeR]

It is really small, here is a better picture:

 

[JoeR]

It is NOT on the new growth, mostly on the main trunk and branches. When I wiped with rubbing alcohol it left a white film over the area??

 

[coh]

I just can't be sure from those photos. There are lots of different types of scale. Some are round and clear or brown, others are skinny (long, narrow) and white...pine scale is like that. Best course would be to scrape it off and see if it looks like there might be something living in there...it would be kind of "gooey" for lack of a better term. Sometimes you can see eggs or even young (crawlers) if it is a female at the right time of year.

I feel like some of my maples may have similar-looking "things" on the trunks. I'll take a look later.

 

[JudyB]

I had the same type of things on a maple a few years ago, and found that it was indeed scale. It didn't look much like the scale that I'd had on my tropicals when I had them, but they were scale. I have used a systemic for a few years, and have not seen any since. If I get a new tree, I'll spray it with Natria, it's a insecticide and fungicide. Takes care of mites, scale and others. It's a Bayer product. I'll only use that if I have a new tree, or have some big problem. The systemic takes care of almost everything else. The active ingredients are suffer and pyrethrins.

 

[Nybonsai12]

Check this page out.

https://crataegus.com/2011/11/29/read-this-if-you-grow-japanese-maple/

The topic is about bacteria on JM however not what your tree has. But if you notice this tree has other white spots that look simiilar to yours. There is no mention of what it is in the article or if it is related, but it is eerily similar.

Scale should rub off entirely and shouldn't leave anything behind. I'm still not sure what you are dealing with is scale.

 

[JudyB]

suffer and pyrethrins.

damn autocorrect! sulphur and pyrethrins....

Could be something else, but easy to figure out if it is scale. They almost pop when you scrape them if they get big enough, and are kinda gooey like coh said. (so funny, autocorrect tried to make coh "cow"....)

 

[MACH5]

I would also like to add that Japanese maples have naturally occurring white streaks on their young bark. This is not to be confused with any kind of disease. The attached photos are not mine but were pulled from the internet.

 

[coh]

damn autocorrect! sulphur and pyrethrins....

Could be something else, but easy to figure out if it is scale. They almost pop when you scrape them if they get big enough, and are kinda gooey like coh said. (so funny, autocorrect tried to make coh "cow"....)

Well, I have been gaining weight the last few months. Maybe that's a sign I need to do something about it!

 

[0soyoung]

Scale is a sucking insect. Sucking insects tap into the phloem or inner bark. They feed on the sugars from photosynthesis.

If you've ever done an air layer, you know how thick the bark is on a branch/trunk a few years or more old. The only places that the phloem is close enough to the surface for them to reach is on the foliage (including the petioles) and newly extending growth.

 

[JoeR]

I would also like to add that Japanese maples have naturally occurring white streaks on their young bark. This is not to be confused with any kind of disease. The attached photos are not mine but were pulled from the internet.

I originally thought it was normal too, but some of the new growth is slightly distorted so it lead me to beieve I may have an issue. The trees are vigorous and seem overall healthy so I suppose it probably is normal like you said. The distortion could also be something else, maybe fertilizer related?


Thanks for the help people!

 

[MACH5]

I originally thought it was normal too, but some of the new growth is slightly distorted so it lead me to beieve I may have an issue. The trees are vigorous and seem overall healthy so I suppose it probably is normal like you said. The distortion could also be something else, maybe fertilizer related?


Thanks for the help people!

Joe, distortion may come about from a variety of reasons and very common in Japanese maples. I don't think there is much to worry about. It happens and usually sorts itself out. When there is truly something wrong with your tree it will let you know. However, always a wise idea to keep an observant eye.