Lots of branches of my weeping cherry tree are covered with powdery substance that seems to kill the smaller branches. Also, quite a few leaves are turning brown and falling off. What to do? Thanks in advance for the help. I live in Massachusetts.
Hi TGH, Can you take a closer look at it with a magnifying glass? Do you see any structure to it, or is it just powdery at that magnification? Do you see any tiny black spots embedded in it? Also can you tell if it starts at the buds/leaves and spreads to twigs and branches, or if there is any apparent spread pattern? Are there spots or any structures/patterns on the leaves before they turn completely brown? At first it looked like lichen on bark, but when I looked at your photo at greater mag, I thought it might be a powdery mildew. Not to get your hopes up, I have no expertise in mildews & friends, but I am now the proud owner of "The Compendium of Plant Diseases," an older book which has been interesting and helpful with mildews, rusts, smuts and other microfungi that cause trouble for plants. - frog
Thanks for the reply, Frog ( I too am a frog, a human frog from France ). Anyhow, a picture is worth a thousand words as they say. Check these out ( tubes + worms?? ) and let me know what you think. Best regards
Re: To all gardening detectives, what is this? Looks like lichen to me. In which case you don't really need to be concerned about it - lichens don't harm the tree in any way, they're just using it for support.
My money's on a white scale of some sort. http://counties.cce.cornell.edu/sch...fruit bearing trees/White Prunicola Scale.pdf
When you said that I got all excited hoping this might be a case of Septobasidium fungus using scale insects to suck sap, which I've heard of but never seen. However unfortunately (for me, not for the tree) none of the descriptions of Septobasidium match this appearance. -frog
Hi, I have a weeping cherry with the same white powdery growth on its trunk and branches. Some of the affected branches have dead leaves and the branches appear to be dying. There are a lot of ants running up and down the branches too. I didn't see any clear recommendations on what to do about the problem. Is there some kind of spray or other treatment that I can apply to fend off what I think is the white scale? Any help is much appreciated, Adam
Seems pretty clear to me. What's confusing you? "I have suggested a ‘power washing’ of heavily infested plants during the dormant season before budbreak, to clean off scale residue and expose crawlers to treatment. Some applicators have even scrubbed bark of infested specimen trees (flowering cherries, e.g.) with a soft brush where appropriate. Check for presence of the tiny dustlike crawlers starting from late April onward. Examine twigs carefully for them or wrap infested twigs with double-sided tape to trap them as they move or blow around. Tapping branches over a white surface can also be used to detect crawlers. We have previously reported two generations of this insect here, but Dr. Raupp feels there may even be a third as in Maryland. This could easily occur especially in warmer years or locations. Crawler activity could also vary by a week or two from one year to the next and in different areas around Long Island, and delayed especially in cooler areas influenced by the ocean. Treat when crawlers are numerous; horticultural oil at summer rates is one option."
Sprays are pretty much the only resort here, since the infestation is so heavy. Since we're into summer, I'd be looking at the summer oils - Neem is fairly good (and less harmful to the environment.)
Thanks for the advice. I have no idea what horticultural oils are, but I will look up Neem and see if I can get some to spray on the tree. Is there a website or vendor you would recommend for this? I already took the step of blasting as much of the white stuff off as possible with the sprayer attached to my hose. Adam
I have absolutely no idea for the US - down here, I can buy Neem oil at my local garden center. Check your local nurseries and greenhouses - it's a fairly common product.
Thank you both so much for your help. I'll see if I can find it locally else I'll order from one of the online sources. Hopefully the poor tree will bounce back.
