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



"paghat" wrote in message
news
I am undertaking a big landscape job here on Puget Sound, and there are a
lot of young paper-birches with birch gall on each side of the property,
mostly twelve to eighteen foot little trees, each with at least a few
"knots" in the higher branches, some with a great many of these knots. I
have to make the decision whether or not to remove all these birches, & am
leaning toward replacing them with fruiting trees. But before I start
getting rid of two dozen young trees, I would welcome opinions from anyone
with experience with birch gall, since this is my first encounter that I
personally had to do anything about, & I'm not at all certain what's best.
Some questions:

Can the birch gall mites infect any other shrubs & trees other than
birches?

The gall isn't apt to damage the longevity or general health of the tree,
but I gather it can make the leaves look pretty crappy. If some or all the
birches are left where they're at, will foliage look pretty decent even
with gall?

I also gather that miticides don't work very well even for the non-organic
gardeners who don't mind using them. I don't want to use such chemicals,
but wonder if there are any risks to just ignoring the presence of birch
gall mites?

Is the standard advice to remove & replace these trees to be taken
seriously?

If I do remove these trees I want to do it now while the mites are dormant
& I have a better chance of burning every one of the little *******s. I'm
hoping they're not apt to attack the ornamental maples or fruit trees
since usually each gall is species-specific & no future birches will be
planted. If they are by & large harmless, though, I could view the two- &
three-inch knots in the branches as being themselves rather ornamental.

-paghat the ratgirl

--
"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"
Visit the Garden of Paghat the Ratgirl: http://www.paghat.com