Nick Maclaren wrote:
In article ,
"Jeff Layman" writes:

The mycelium that appears on compost will correspond to a
saprophyte; virtually the only organisms that cause trouble are
parasites; they don't overlap all that much.

I don't understand. Are you saying that the fungi which cause
damping-off are parasites? Did you mean pathogens?

There is a difference? Seriously. The difference betwen a parasite,
a predator and a pathogenic organism is more a matter of religion than
science :-) What I mean is that they live by destroying living plant
cells, and not dead (in this case, probably woody) material.

Some organisms attack both, but not all that many.

There is a great difference.

Parasites will not be pathogens if they remain below a level which is
pathogenic. You may have a tapeworm or other intestinal parasites of which
you are completely unaware because they have absolutely no effect. You may
be eating more to compensate for what they are taking for their own
purposes, but that's all. Of course, if you get a heavy infestation, you
will suffer malnutrition. Then they may be considered pathogenic.

I admit that the difference between a parasite and predator is more vague.
However, a parasite tends to be passive, while a predator is active. In
addition, a parasite may not even harm its host. A predator tends towards
lethality...

As far as the plant world goes, fungi can fill almost every niche -
saprophytes, pathogens, symbiotes, commensals (? maybe). But perhaps not
predators, although I am happy to be corrected.

--
Jeff
(cut "thetape" to reply)