First of all, howdy. I've been lurking for about a week, and very much
like the tone and content here. I'm a long time user of newgroups
(specifically rec.music.a-cappella, and alt.music.a-cappella back in
the early 90's), and it's nice to find a new community for a my new
hobby (now that I have a garden).

Onto the question (the first of many, I'm sure):

I live in San Francisco, and recently (April, 2003) bought a house
with 3 dwarf apple trees in the back yard. All were infested with
wooly aphids. I like to keep an organic garden, so I was told by
several sources that my best bet was to squirt them off with a hose.

And squirt I did. All summer and fall. It was like a carnival game,
but the balloon never popped.

I kept the trees clean, and yet the little monsters would come back.
At first every day or two, then twice a week, then once a week, and
now I hardly see them.

In the summer, the sunniest tree was covered with leaves, and by fall
it provided a nice harvest. The largest tree, second sunniest, was
covered with leaves, and sent up some verticle shoots, but never bore
fruit. I'm bullish that it'll be in full force next year.

However, the third tree, the runt (3 feet high) and least sunny of the
three, is still a sad sight. A few full-size leaves, and some tiny
ones, but mostly a skeleton.

I understand wooly aphids go underground this time of year, attaching
themselves to roots. It's not unlike the Alien from the movie of the
same name - keeps changing form, keeps coming up with new ways to make
your life miserable.

All of the builds up to the following questions:

1) What are my runty tree's chances?

2) If it's likely to die, would I be doing my other trees a service by
pulling it up, bringing the root-born aphids with it, or would they
jump ship and go bother my other trees?

3) Is there anything I can do during the winter to fight these
monsters?

4) Next year, what should I do to hopefully be rid of them once and
for all? I read somewhere that the'll change form once again, and send
crawlers up the trunks. Is this right? Will fatty acid soaps do the
trick (they're not much effective when the aphid is in "wooly" stage,
protected by the "wool," but will that be gone in the next
incarnation? Any natural pests (the regular aphids on my Meyer Lemon
tree became a tasty snack for ladybugs)?

5) Anything else I should know?

Thanks!
- Deke Sharon

Deke Sharon said:


However, the third tree, the runt (3 feet high) and least sunny of the
three, is still a sad sight. A few full-size leaves, and some tiny
ones, but mostly a skeleton.


1) What are my runty tree's chances?

A badly located tree is never going to thrive. It could struggle on for
quite a while, attracting pests and requiring extra attention. It might
be best to pull the plug.

2) If it's likely to die, would I be doing my other trees a service by
pulling it up, bringing the root-born aphids with it, or would they
jump ship and go bother my other trees?

How long is the crawl over? Is the runty tree upwind of the others?

3) Is there anything I can do during the winter to fight these
monsters?

The Organic Method Primer UPDATE suggests gently digging around
the base of the tree looking for aphid galls on the roots, which can be
pruned away and destroyed. It also suggests using beneficial nematodes
to attack any colonies on the roots.

4) Next year, what should I do to hopefully be rid of them once and
for all? I read somewhere that the'll change form once again, and send
crawlers up the trunks. Is this right?

According to what I just read, they have an alternate host on elm trees, which
they feed on in the early spring for two generations before moving back
to apple trees. (Underground root-gall colonies are continuous.) Any elm
trees in the neighborhood?

Will fatty acid soaps do the
trick (they're not much effective when the aphid is in "wooly" stage,
protected by the "wool," but will that be gone in the next
incarnation?

Consider using oil sprays (Organic Method Primer UPDATE).

Any natural pests (the regular aphids on my Meyer Lemon
tree became a tasty snack for ladybugs)?

Same source noted above:
Chalcid parasitoid wasp, _Aphelinus mali_
syrphid flies
ant lion
Clover is recommended to support enemies of the aphid.


[I 'rescued' a plum tree on the property that was badly infested with
scale; another was too far gone. However, the tree is not well located
and still struggling. And varmints eat all the plums that the bugs don't
get. Thirteen years and it's still hanging on, barely...]
--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)

Thanks for the lengthy, thorough response

A badly located tree is never going to thrive. It could struggle on for
quite a while, attracting pests and requiring extra attention. It might
be best to pull the plug.

It has fruited in years past, but that doesn't mean it will.

A related question - were I to plant a new fruit tree in its place,
would I be wise to stay away from apple (or pear?), so as to not give
the aphids a new similar food source?

How long is the crawl over?

from tree to tree? Perhaps a yard. This is a San Francisco backyard,
after all

Is the runty tree upwind of the others?

yup

The Organic Method Primer UPDATE suggests gently digging around
the base of the tree looking for aphid galls on the roots, which can be
pruned away and destroyed. It also suggests using beneficial nematodes
to attack any colonies on the roots.

Ah - good suggestion. Probably not a backyard chore while my 3 year
old is around. What nematodes does it suggest.

And wht is the OMPU $200 on Amazon?!?

According to what I just read, they have an alternate host on elm trees, which
they feed on in the early spring for two generations before moving back
to apple trees. (Underground root-gall colonies are continuous.) Any elm
trees in the neighborhood?

The closest possible one would be in Golden Gate Park - a minimum of 2
blocks away.

Deke Sharon said:

A related question - were I to plant a new fruit tree in its place,
would I be wise to stay away from apple (or pear?), so as to not give
the aphids a new similar food source?

IMHO yes, so as also to give yourself an alternative fruit!


How long is the crawl over?

from tree to tree? Perhaps a yard. This is a San Francisco backyard,
after all

A, sounds doable.

Is the runty tree upwind of the others?

yup

Very doable....

The Organic Method Primer UPDATE suggests gently digging around
the base of the tree looking for aphid galls on the roots, which can be
pruned away and destroyed. It also suggests using beneficial nematodes
to attack any colonies on the roots.

Ah - good suggestion. Probably not a backyard chore while my 3 year
old is around.

Oh, they don't harm people and applying them involves pouring or spraying
solution and then watering them in. Might even be fun.

What nematodes does it suggest.

Doesn't mention specifically. I the Hh or Hb species are better at going after
underground insects. (The Sc nematodes are better for near-surface.)

Another thing you could do is give the trees some TLC in the form of
foliar feeding (with seaweed spray -- I use Maxicrop) and mulching with
compost.

And why is the OMPU $200 on Amazon?!?

The culmination of the life-work of Bargyla Rateaver, self-published, low-volume.
She is elderly and the book sales have been a source of income.

Any elm
trees in the neighborhood?

The closest possible one would be in Golden Gate Park - a minimum of 2
blocks away.

Close by, then, in terms of a generation of flying aphids.

--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)