Japanese maple disease identification. Please help b

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

mbsfield

ArboristSite Lurker
Joined
Nov 14, 2016
Messages
29
Reaction score
4
Location
US
Can anyone identify what this issue might be?

8035b390d45e7b10b64d8b4c9e426369.jpg
54afc304809fc7dd8e38934611429f46.jpg


Sent from my SM-N910T using Tapatalk
 
That looks like scale insect. I've always used horticultural oil for scale, but it can be tough to eradicate. generally infestations happen due to stress on the plant. is this a new planting? if not new, has anything changed around the tree? like building a new structure or removal of a structure (like a fence/shed or paving, etc.
 
After looking at the pics again, have all the ties to the support stakes been loosened or removed? (Including name labels). that can lead to problems as well.
 
That looks like scale insect. I've always used horticultural oil for scale, but it can be tough to eradicate. generally infestations happen due to stress on the plant. is this a new planting? if not new, has anything changed around the tree? like building a new structure or removal of a structure (like a fence/shed or paving, etc.
No, this tree is 4 years old and has been in this pot for around a year now. The only thing that's changed is the season. The top canopy is somewhat spotted. I couldn't identify as to why though.

Sent from my SM-N910T using Tapatalk
 
Yes, all of those have been removed. On the other hand, I did add some ivy and some firebud flowers to the pot in the spring. The firebuds tag is still in there. I poured a cup of coffee grinds into the pot last week. Although, it does look like there is a tie on the tree in this pic, I'll look again.

After looking at the pics again, have all the ties to the support stakes been loosened or removed? (Including name labels). that can lead to problems as well.


Sent from my SM-N910T using Tapatalk
 
If you Google 'scale on Japanese maple' it will show pics that are much like your tree issue. if the tree is in a pot it sound like it may easy enough to eliminate a major portion by hand. you should be able to wipe them off on most of the stems using your hands. in tighter areas like narrow crotches i would recommend using a horticultural oil mixed for summer use,, spraying weekly and first thing in the morning, until the tree has gone dormant. then change to a winter mix.
 
If you Google 'scale on Japanese maple' it will show pics that are much like your tree issue. if the tree is in a pot it sound like it may easy enough to eliminate a major portion by hand. you should be able to wipe them off on most of the stems using your hands. in tighter areas like narrow crotches i would recommend using a horticultural oil mixed for summer use,, spraying weekly and first thing in the morning, until the tree has gone dormant. then change to a winter mix.
I touched one yesterday and it did seem to wipe off easily. I will do that. These pictures are actually pretty clear, so I'm not sure why the post isn't. The little scales look like Hershey kisses and one looks like a bonnet or shower cap(just for clarification since the pic is blurry). I will remember to look that up once I get home.

Sent from my SM-N910T using Tapatalk
 
The pics were good.... and the post was clear. I was just asking about stresses to see if there was a reason the maple became infested. sometimes it just happens, and sometimes there is something else that causes the plant to be more susceptible.
After hand cleaning I would definitely follow up with an oil spray. and your local nursery should be able to recommend a brand for you. just make sure it is for summer and winter use and it should be 100% Parafinnic oil.
 
The pics were good.... and the post was clear. I was just asking about stresses to see if there was a reason the maple became infested. sometimes it just happens, and sometimes there is something else that causes the plant to be more susceptible.
After hand cleaning I would definitely follow up with an oil spray. and your local nursery should be able to recommend a brand for you. just make sure it is for summer and winter use and it should be 100% Parafinnic oil.
Thank you for the help, it's greatly appreciated. There probably is some stress though. The leafs were beautiful until last month. The pot may have become too dry while I was out of town, it seems like the leafs took a hit after that. At first I thought the sun was too intense, but my parents trees are fine (and they see much more direct sun than mine). Other than than, I'm not exactly sure what might be stressing the tree.

Sent from my SM-N910T using Tapatalk
 
My first thought is cottany maple scale.
I could see why that would cross your mind. After a review of the scale, it definitely is not that. These seem squishy and wet. There were some images that looked similar, though.

Sent from my SM-N910T using Tapatalk
 
ruling out scale leaves only mealy bugs.
I would use the same treatment already recommended.
as for the spots on the leaves.... Without seeing a pic I can't say with total certainty if anything needs to be addressed.
 
ruling out scale leaves only mealy bugs.
I would use the same treatment already recommended.
as for the spots on the leaves.... Without seeing a pic I can't say with total certainty if anything needs to be addressed.
I think it's still scale, just not cottony. These don't appear to be mealy bugs either, could be a different for I suppose.

921b961caec71dbdbcf7b8b1477bc0f8.jpg




Sent from my SM-N910T using Tapatalk
 
I think it's still scale, just not cottony. These don't appear to be mealy bugs either, could be a different for I suppose.

921b961caec71dbdbcf7b8b1477bc0f8.jpg




Sent from my SM-N910T using Tapatalk

The strange thing is, I just knocked them off and there was zero damage at the attachment site.

Sent from my SM-N910T using Tapatalk
 
You mentioned
These seem squishy and wet.

That has me leaning more towards mealy bugs. both scale and mealy bug are sap sucking insectso rather than chewing like slugs or caterpillars, so damage is not immediately apparent. it generally shows as distorted new growth.

With a little better view of the leaves, i am thinking that is stippling i am seeing on them. that could be spider mites, which are very very tiny sap sucking insects.

What part of the country is this and is the dtree kept outside and exposed to the elements?
the fact that the tree hasnt started into domancy im guessing you are maybe inland southern california... or near anyways.
 
You mentioned


That has me leaning more towards mealy bugs. both scale and mealy bug are sap sucking insectso rather than chewing like slugs or caterpillars, so damage is not immediately apparent. it generally shows as distorted new growth.

With a little better view of the leaves, i am thinking that is stippling i am seeing on them. that could be spider mites, which are very very tiny sap sucking insects.

What part of the country is this and is the dtree kept outside and exposed to the elements?
the fact that the tree hasnt started into domancy im guessing you are maybe inland southern california... or near anyways.
I'm perplexed by my this as a whole. No, I'm actually in mid Alabama. The weather is oddly hot for this time of year.

Sent from my SM-N910T using Tapatalk
 
Hort oil is acceptable to use for treatment of both issues. if you are still wanting a definitive i.d. take a stem to a local nursery.
 

Latest posts

Back
Top