Wayne Forrester's position on the non-use of nicotine extracts
from tobacco has been long accepted in orchid growing circles.
The nicotine in a contained in a single cigarette is sufficient to
poison a man and even kill him, if injested. The LD-50 of nicotine sulphate,
which is the commercially available form of nicotine insecticide,
is tiny and that amount can be absorbed directly through exposed skin.
Restrictions on its used are quite severe because of the danger involved.
TMV is highly stable against heat inactivation and in dry environments. It
crystalizes(forms crystals) when dry but remains infectious. I have seen
articles about TMV being shown to be present in smoke from the burning end
of a cigarette. Sorry, again no refs. but I did see it.
Many TMV strains have been demonstrated to infect orchid plants
and other genera. It is likely that many strains also infect cp.
Recalling viral assey experiments in university; we transmitted TMV from one
plant to another by simply rubbing leaf sufaces lightly with infectious
sap(extract) on our fingertips.
Plant viruses result in colour phase disruptions, deformed growth, general
loss of vigor or death in most plants. They may be passed on to following
generations through seeds(trans-ovarian injection) and there is no cure for
infected plants.
(except cloning, sometimes)
Using tobacco extract is probably not a very good idea. I agree with Wayne.
Al Bickell
CTC Labs