In article , Franz Heymann notfranz.
writes


Kay, could you do a bit of explaining please:

I presume that the development of a resistance to a pesticide is a genetic
process. I envisage it as occcuring when one specimen undergoes a genetic
modification in the desired direction, and subsequent sexually transmitted
mixings spreading it through a population. If this is so, I don't think one
will notice as quick an immunity as you imply.

Please tell me what I misunderstand.


I'm talking about a time scale of years rather than months. A greenhouse
is a largely closed environment, so it's more of a problem than the
garden generally. Certainly I no longer find pesticides effective
against mealy bug and red spider mite.

Generations in both mealy bug and rsm come thick and fast!

--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/edward/index.htm