Weird white fungus on River birch - Ask Extension
I have a 7 yo River birch with the following symptoms:
1) some leaves are yellowed/brown with deep curling/warping of the tissue
2) in the folds of th...
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Weird white fungus on River birch #252112
Asked June 07, 2015, 9:01 PM EDT
I have a 7 yo River birch with the following symptoms:
1) some leaves are yellowed/brown with deep curling/warping of the tissue
2) in the folds of the leaves is this fungus-looking white material. It does not appear to be of animal origin.
3) I have observed at least 3 species of wasp attracted to this stuff but not observed any feeding.
4) those affected leaves are also attractive to larval lady bugs and adult stages
5) if it's aphids, this looks like no aphid I've ever seen. I have photos if you need them.
Jefferson County Kentucky
Expert Response
Please attach photos and respond to this original message stream.
I planted a witch hazel (10 gal pot) one year ago. If it is these, do I need to protect it from the next part of the aphid life cycle?
I agree with your diagnosis. Here is a fact sheet I found from Clemson University that talks about this insect: http://media.clemson.edu/public/esps/pdfs/to17.pdf. It seems that typically little long-term damage is caused by this pest to river birch. Should you decide to treat either the river birch or the witch hazel, I would recommend using a soil drench containing the active ingredient imidacloprid. It is available from several companies and is usually sold under a name like tree and shrub drench. Follow label directions. At this time of year I would only treat the witch hazel and possibly treat the river birch early next spring when the leaves are starting to erupt from the buds. This is the time the new leaves will be infested and when control will be most effective. Interestingly, since this aphid requires alternate hosts to complete its life cycle, you should actually only need to control it on one or the other plant.
Thank you for your confirmation of the aphid.
