"Claudio Fierro" wrote in message
...
Thanks again everybody for the valuable information. Now I
understand
it isn't a good idea to use pesticides in a preemptive way;
but, can
someone explain to me why we can do it for funghi?
Thanks.
Claudio.

And Andrew explained cogently:

You don't always do it for fungi, and apart from in my job at a
golf course
I have never done it elsewhere.
The reason it can be done is fungal attacks can be predicted.
e.g. Humid weather can bring on specific fungal attacks, as can
a lot of
rain. Also certain plants may be prone to certain fungal
attacks in your
local area.
I know Azaleas in my local area are very prone to petal blight,
as are
roses. This is due to the humidity here
Still there is no harm in spraying at the very first signs of
it.
The main points to remember if you are going to spray fungicide
preemtive
a
1) Know the disease first so you use the correct chemical
2) Spray at correct time. This may be at a particular time of
year, or just
after constant rain or humid conditions. Again, depends on
fungus, local
conditions and particular plant/s. No point spraying at wrong
time, as it
does nothing and wastes money.
3) Try and rotate fungicides. Here in Australia (and I assume
most other
places) chemicals are classed into groups (A, B C etc). You may
choose to
spray group A for a year, then the following year, group B,
then back to A
the next year. Of course these letters are eg only, fungicides
may be
different group letters. Also the fungicide will have a
different name, so
be sure that between swapping groups they will attack your
target.
Failure to swap groups or over use of fungicides (or any
chemical) can cause
resitant fungus (and pests), then you may never get rid of the
target and
may lose the plant in worse cases.


To which I add acerbically:

READ THE LABEL

Jim Lewis - - Tallahassee, FL - Bonsaiests
are like genealogists: We know our roots!

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