I planted this maple about 2.5yrs ago. It did well the first summer. Then last summer it appeared as though the leaves were all "burnt" - not all, mostly the top leaves that got the most sun. Now this spring it appears to be starting again plus I am noticing black spots on the leaves. Also there are insects- looking like fruit flies on the underside of some of the leaves. Not sure if these are related to the problem. Can anyone advise what this is and how to treat?
More information would help the possibility of answering this question. What type of maple is it? Is it possible to post photographs of the damage?
Sorry - it is an acer shirawsawanum aureum - adding pics is easier said than done - have attached 3 to original post but they keep disappearing. will try again...
Ah, shirasawanum 'Aureum' can have sunburn issues in full sun depending on exposure and location. See if this is any help with attaching the photos: How to Attach Photos and other files
thanks, yes I think it may be sunburn. It is full sun, southern exposure. But i don't think the black spots match the burn....If it is - is it too late to move after 2.5years? trying again with the attachments from a different computer....
I would rather suspect a kind of fungus: what's the weather like at the moment in Vancouver? Here, we've had a very wet spring so far, and some of my trees are beginning to show the same kind of symptoms. I'm interested in reading the replies from more savvy maple buffs...
One possibility is bacterial leaf spot (Pseudomonas syringae). Have you noticed any small twigs turning black and dying, then turning ash grey, spreading from the tip downwards? http://pnwhandbooks.org/plantdisease/maple-acer-sp-bacterial-leaf-spot-and-dieback The insects look like aphids from what I can see in the pics. All of the yellow/green cultivars of Japanese maple seem more susceptible to these leaf spotting diseases than the green or red types. Some years seem to be worse than others, and I seem to notice it more when the weather is a mixture of showers and sunshine, wet and fairly warm.
Sometimes they do, sometimes they don't. From http://www.entomology.umn.edu/cues/inter/inmine/Aphids.html:
Thank goodness for that! :) re: the AS Aureum. While I don't qualify myself as an expert, I don't see the need to look further than sunburn. The washed out leaves that shade healthier leaves are an indication. The maple may also not be getting enough water to support leaf transpiration. I have seen this in poorly established yellow leaved maples here. (2.5 yrs may not be enough for the plant to be fully established in the landscape). Yes, you can move it, just try and get a good root ball (and do it in late fall after leaf drop or early spring before the sap starts to rise). If you have a spot with more shade, that would be better for this particular maple. If you can reach the plant with a hose, clean the aphids off with that. Otherwise you can remove them by hand if there aren't that many, or in case of a bad infestation use a chemical treatment. Be careful with this last as some treatments damage young leaves.
Thanks all for the info. Re bacterial leaf spot- yes we have had a wet and warm spring - just as you described but no black twigs so far..... I just gave the aphids a good hose down, as I did the week before and they don't seem to be proliferating - although I just discovered a new crop of aphids on my newly planted apple tree- and a nearby elderflower. I guess this will be my new challenge and I will wait til autumn and re-evaluate the maple.
