RE: pnw-spineless-digest V2003 #8

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FWIW, Whitefly tend to hang out on the undersides of the leaves. The usual
organic control is to spray with various solutions of soapy water (sometimes
with a dormant oil or rubbing alcahol) on the UNDERSIDE of the leaves. In
other words, with your sprayer, walk around the affected bushes pointing the
tip of the sprayer up into the foliage so it hits the bottoms of the leaves
and drips down, rather than the more usual way of doing things. At one point
i had a nice little one gallon pump sprayer... I wonder what happened to
that thing. Anyway, my favorite mix was a tablespoon of rubbing alcahol+ 2
tablespoons of dish soap (blue dawn works great, but any reasonably
efficient soap should do the trick) and a gallon of water. Hopefully the
alcahol won't be strong enough to burn any leaves in the process. With salal
and other tougher leaves, this shouldn't be a problem, but be careful of
newly budding sprouts this time of year- the alcahol will literally dry them
up. A tablespoon of oil might help to get the stuff to stick (and not
incidentally to smother the bugs as well...)

But then again, these sprays have the same effect as any other pesticide if
the predators are already present. They kill ALL the bugs under the leaves,
whitefly and predatory beneficial.

I would take a very close look at the plants and see if they are suffering.
These (as well as aphids, scale and other sucking insects) can get numerous
enough to do some real damage, especially in early spring to new buds coming
in. Contorted growth is not uncommon on heavily infested plants. Its also
mostly cosmetic. But if the growth starts drying out and you get secondary
infections of things like sooty molds from aphids, powdery mildew, blackspot
or mosaic viruses these can combined with the already weakened state of the
plant lead to branch dyoff or ultimately in really bad cases death of the
plant. I sometimes wonder if this is what led to the demise of my first
red-flowering currant- first it got ants farming aphids in the summer, then
bad cases of powdery mildew two springs in a row, followed by odd flowering
seasons, starting mid-winter. The bush finally dried up one summer, probably
from a form of root rot combined with the powdery mildew.

Brett Johnson
Green Man Gardens
bnbjohns@attbi.com


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