poplar condition

I have a poplar tree in my front yard, which was there when I bought the house. I was only told that it's a "poplar". The thing grows like a weed, I don't think there's been a year when it failed to put on at least 5 feet.
There has been a spot on one of the roots for a few years where it has a very odd growth, and this year, the new, small branches have developed similar growths. I haven't been able to find similar growths in my googling, so I'd like to hear if anyone can tell me what this is. Hopefully it's something that the tree can overcome, but if not, the thing is big enough (and grows so quickly) that it would be better to take it out sooner rather than later.
A picture of one of the growths can be found at:
http://codon.com/poplar.jpg
Thanks in advance.
steve
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Steve Wolfe wrote:

It's a gall, maybe Petiole Gall of Poplar. It's unsightly but not dangerous.
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Thanks for the tip on it being a gall. To my untrained eye, it looks like it may be a crown gall:
http://soilplantlab.missouri.edu/plant/diseases/crowngall.htm
Thoughts?
steve
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Steve Wolfe wrote:

Split one open, if there are no chambers inside then it's probably caused by bacteria (crown); if there are chambers present then probably caused by insect (aphid, mite, moth, etc.) If you can't ID it, play it safe, prune off and burn them.
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Thanks, I'll split one.
steve
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Steve Wolfe said:

Maybe poplar bud gall mites:
http://nofc.cfs.nrcan.gc.ca/publications/leaflets/poplar_gallmite_e.html
--
Pat in Plymouth MI ('someplace.net' is comcast)

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