In article ,
Lazarus Cooke wrote:
In article , Nick Maclaren
wrote:

Basil (Ocimum basilicum) originated in tropical Asia, perhaps India,
and has been cultivated for a VERY long time. The prevalence of
parasites is strong evidence of an origin in a similar ecology.
Also, it is a perennial in its natural habitat but, like many tropical
perennials, will grow as an annual in colder climates.

Thanks for this. I think it may have been you, nick who pointed out the
tropical origins?

But (blushes), I didn't quite get the full gist of your point about the
parasites? Could you expand? ( I *think* I understand, but might be
wrong, ok?)

Generally, after a long time, organisms settle down in adaptation to
their environment, and that includes their relationships to parasites.
Thus a sign of an ancient parasite is that it does not kill or even
seriously debilitate its host - though things aren't quite that simple.

Equally, a sign that an organism is not in its natural environment is
often that it is NOT attacked by parasites or (occasionally) that it
is attacked and killed by them. The latter is more often indicative
of a parasite that has been introduced from elsewhere, of course.

Take a look at wild plants and/or weeds, and you will see that they
normally have low levels of parasitism - rust on weeds is an obvious
example in late summer - but they don't seem to be seriously harmed.
That is USUALLY evidence that they have evolved together.

One of the main reasons that prickly pear became a pest in Australia
was that it had no parasites in that environment; the solution was to
introduce one :-)


Regards,
Nick Maclaren.