In article 7Fdmd.91590$HA.82267@attbi_s01, "Pam - gardengal"
wrote:

I would second the opinion to confirm your diagnosis. If they are birch
budgall mites, unless the infestation is severe there is no need to do
anything. Otherwise, some judicious pruning is in order. And no, that
specific mite is unlikely to bother anything other than birches. Leaf gall
aphids do no damage to anything other than foliage - you would not detect
any noticeable woody or knobby galls on stems or branches and they too are
not inclined towards other species. OTOH, European white birches develop
what are referred to as "galls" of dormant buds, which paper birch do not -
are you certain of your ID? EWB's, while not native to this area, are
somewhat naturalized and do spring up spontaneously.

Either way, unless they are aesthetically displeasing or it is crown gall as
Toad suggests (uncommon in the upper branches of a birch), removal is not
necessary and no control other than pruning out of obvious stem galls is
recommended.

pam - gardengal

Thanks to you & Toad. There is one Young's white birch on the property &
it's the only birch unaffected. All the paper birches have the woody
knobs, all higher than arm's reach. So I'll regard them as no real threat
& just try to trim off what I can.

-paggers

--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
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