However, I'm more confused now than ever. I'm not sure now
whether my maple
is suffering from powdery mildew, woolly aphids or what. The
lower leaves
seem to be the most affected, and the powdery white stuff is on
the
underside of the leaves. It is a fine white powder with some
larger masses.
This seems to mean it may be woolly aphid instead of powdery
mildew?
Also I found what looked like a mealy bug on it today. Would a
mealy bug
infestation result in the white stuff on the leaves? To be sure
I'm
continuing with the copper oxychloride and have started
spraying with
insecitcide.

STOP! You'll kill the tree. Mixing chemicals on a tree's leaves
creates (or may create) new chemicals that only a Phd chemist
could figure out. You may be endangering your tree as well as
kids, cats, sacks and wives (in or out of St. Ives).

Do NOT spray your tree with something unless you KNOW that
whatever is on your tree is an appropriate target for that
chemical. In other words, read the label and follow it.

How do you find out what's on your tree? Well, as you have
discovered, asking for a sight-unseen diagnosis here leaves you
with a shotgun response one of whose pellets of information may
or may not be correct.

There are three more or less reliable ways to identify an insect
or disease on your tree.

The most definitive is to take a leaf (or leaves) to your local
agricultural extension office (or for folks in other countries
who don't have these valuable community tools, a local
agricultural departement in a university) or a GOOD nursery (NOT
Wal-Mart or Home Depot types) and have someone ID the problem.

Second option is to buy either the "Ortho Home Gardener's Problem
Solver" or the "Southern Living Garden Problem Solver" (Sunset
may have one, too) and find the insect, disease, or fungus, etc.
there and follow those recommendations.

The third (and most questionable, accuracy-wise unless you are
careful) is to use the web. Try:
http://ohioline.osu.edu/hyg-fact/2000/index.html
http://www.npwrc.usgs.gov/resource/2...t/families.htm
http://www.uky.edu/Agriculture/Entom...ts/eftrees.htm

My one-time favorite bug pages at the University of Florida seem
to have vanished. UoF has a web"master" who can't stop diddling,
and a page doesn't stay in the same place long enough to bookmark
:-(

I've isolated it and put it in a position with good air
circulation and sun (I think this is part of the overall
problem I'm having
with many of my plants - overcrowding. Too many plants in too
little space.
Well, I can't help myself, I see it, I like it I buy it. Just
have to make
more room :-).

I'd suggest a bit of self-control here. Until you get to knowing
what you are doing (which includes identifying the common pests
and plant diseases in your area) you will lose more than you
save.

Jim Lewis - - Tallahassee, FL - Our life is
frittered away by detail . . . . Simplify! Simplify. -- Henry
David Thoreau - Walden

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At 04:57 PM 4/13/03 +1000, James Quinan wrote:
Hi all,

Firstly, thank you to all those that took time to give me feedback on my
problem. Muchly appreciated.
However, I'm more confused now than ever. I'm not sure now whether my maple
is suffering from powdery mildew, woolly aphids or what. The lower leaves
seem to be the most affected, and the powdery white stuff is on the
underside of the leaves. It is a fine white powder with some larger masses.
This seems to mean it may be woolly aphid instead of powdery mildew?

James

You are going to have rule out mites and other creatures. You can do this
with a hand lens or lupe. I think I already gave you this link, which you
can use to confirm or eliminate the possibility of mites:

http://www.evergreengardenworks.com/mites.htm

If not mites, but some other insect or pest, you will be able to find out
with a hand lens. Powdery mildew doesn't crawl around or leave eggs. Get a
lens, it is a mandatory part of engaging in horticulture.


Brent in Northern California
Evergreen Gardenworks USDA Zone 8 Sunset Zone 14

http://www.EvergreenGardenworks.com

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To be sure I'm
continuing with the copper oxychloride and have started spraying with
insecitcide.

[/nag mode on/]This is the problem with treating a problem without
knowing what's wrong: You're using at least one unnecessary
pesticide. Nowadays the EPA has stopped worrying about individual
exposures to individual pesticides, and is concentrating on figuring
out the effect of lifetime exposure to all pesticides. You should
try to minimize your overall exposure. [/nag mode off/]

Woolly aphids are furry white lumps. They will scrape off with your
finger, and if squished, will bleed aphid blood. They are hard to
treat with insecticides because their "wool" is hydrophobic. Summer
oils will work, but these tend to be phytotoxic to maples. If it
were my maple, I'd scrape off the adults by hand, and treat
periodically with a contact insecticide like a pyrethrin to catch the
"crawlers" (immature, thin-skinned stage).

Spider mites, if they reach really high levels, will cause extensive
webbing on the underside of leaves. But it doesn't look like powder:
it looks like webs. Washing the leaves with a hard stream of water
periodically will usually get rid of them; if not, pyrethrin sprays
will.

Powdery mildew generally causes white powdery spots on leaves. It is
only mildly harmful to trees unless they are being kept in bad
conditions with poor air circulation. Part-sun and good circulation
will solve the problem better than a fungicide.[And you have to
believe me on this, because I am one of the US's powdery mildew
experts. Once in a while I actually know what I'm talking about].

Let us know if you figure out what the maple actually has: If you
want to cut to the chase, take the tree to your nearest county
Cooperative Extension office, and they'll be able to give you a
positive ID. Good Luck!
--
Nina Shishkoff

Frederick, MD

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