Re: [nafex] Captan - Chemical Half-life

["Gordon C. Nofs" <gcnofs@hotmail.com>]

Tom
   Captan with a mixed PH of 10=12 minutes, with a PH of 4=4 hrs.
Roundup with a pH of 3.5= optimal effectiveness.
Malathion: Hydrolysis is rapid at a pH just above 7.0 or below 3, optimal is 
5 to 6pH.  pH of 10= 0.7 days, pH 8=6 days, pH 7=21 days, pH 6=55 days, pH 
of 4= 315 days.

   Hard water is the worst enemy of mixes. Ions in the hard water interact 
with the salts in the herbicide formulation essentially tie up the 
herbicides, so it says here. Didn't you get the information on proper pH for 
spray mixtures? If the right pH is way off the spray is no good by the time 
you reach the spray area.
       Gordon
*************************************************
I know some of you have little use for chemicals, but I want
to share something I just learned with other novice chemical
users.

Not too long ago I carefully measured out a gallon of water,
and the proper amount of captan to make up a gallon of
fungicide for spraying on cuttings.  (Took all the necessary
precautions).

What I just learned today is the half life (time it is
effective) of captan in water is 2.5 days.  Malathion is
shorter, just 1 day.

Not knowing this, I have sprayed a lot of useless chemicals
in the past few years.  Not using a lot of spray at any one
time, I would save the extra in carefully capped bottles,
and use it the next time.  Boy do I feel sheepish.

Here is a web page that contains the half life of some
selected chemicals;

           http://wizard.arsusda.gov/acsl/ppdb3.html

So I guess the lesson is that being frugal does not always
work.


Regards,
Tom
--
Thomas Olenio
Ontario, Canada
Hardiness Zone 6a


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