The definitive study on the use of caffeine to rid orchids was
published in Nature, 27 June, 2002
(www.nature.com/nature)
The work was carried out by Robert G. Hollingsworth, John W.
Armstrong and Earl Campbell,
US Pacific Basin Agricultural Research Center
USDA Agricultural Research Service
PO Box 4459, Hilo, Hawaii 96720 USA
e-mail: [EMAIL PROTECTED]
To quote in part:
We then carried
out two greenhouse
tests in which caffeine solutions were
applied to the growing medium of potted
orchids infested with Z. arboreus. In the
first test, 1 and 2% solutions of caffeine
were associated with 60 and 95% mortality,
respectively (control mortality averaged
10%). In the second, larger test, a 2%
solution of caffeine proved to be more
effective in reducing the presence of snails
than a solution of 0.195% metaldehyde, the
commercial standard for orchid-snail treat-
ment. Over 30 days, 5 snails were extracted
from the medium treated with caffeine,
whereas 43 and 35 snails were collected
from media treated with water (control)
tests in which caffeine solutions were
applied to the growing medium of potted
orchids infested with Z. arboreus. In the
first test, 1 and 2% solutions of caffeine
were associated with 60 and 95% mortality,
respectively (control mortality averaged
10%). In the second, larger test, a 2%
solution of caffeine proved to be more
effective in reducing the presence of snails
than a solution of 0.195% metaldehyde, the
commercial standard for orchid-snail treat-
ment. Over 30 days, 5 snails were extracted
from the medium treated with caffeine,
whereas 43 and 35 snails were collected
from media treated with water (control)
and metaldehyde,
respectively.
For reference, strong coffee contains about 0.5% caffeine (see
http://wilstar.com/caffeine.htm)
Caffeine is, of course, water soluble, so I don't believe they
would be at all effective.
I make no representations of the actual effectiveness of the
treatment, or its not being toxic to orchids but remember caffeine can
be toxic to people if OD'd.
A source of 'pure white crystalline powder' caffeine:
http://www.aonevitamins.com/caffeine.htm
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