"Mark. Gooley" wrote in message ...
I saw some product sold as a sort of horticultural disinfectant,
with a mention that it could be sprayed on roses with black spot
as it would kill any live spores on contact. It turned out that it
was "hydrogen dioxide" at a concentration of 27% or so.

Now, as far as I know, that's a synonym for hydrogen peroxide,
and the drugstore stuff can be as cheap as $1 a quart for the usual
3% solution -- about a tenth as strong. So suppose that one put a
pint or quart of the cheap stuff for each gallon capacity of a sprayer,
and diluted it. Spraying it on any live black spot spores (and one
would hope, various other fungal spores, and perhaps some fungal
infestations) would kill them, presumably. Now, it's not a sure cure,
it's not a long-term preventive, but it's certainly cheap and it's certainly
not toxic. Anyone tried it? Any thoughts?
.......

Take care handling 27% H2O2; it can cause corneal burns if it
gets in the eyes. I'd use goggles and rubber gloves. It isn't
poisonous, but it -can- burn skin and mucous membranes.

Concentrated H2O2 is nasty stuff--a very strong oxidizer.

During WWII the Germans used 90% H2O2 for rocket fuel.


If the instructions really say to dilute to 1/10 strength, it may be
cheaper to use the drugstore stuff straight out of the bottle.

The breakdown products are water and oxygen, and it decomposes very
rapidly on
contact with organic material and certain metals, such as iron,
copper and silver.



J. Del Col