In article ,
Bob Hobden wrote:

Regarding your present situation, you need to remove the infected plant
totally and burn it or take it to your Council recycling plant and put it in
the general waste NOT the green waste. Keep a good eye on the remaining
plants and do not get water on them when you water to ensure the leaves stay
dry, Blight needs damp leaves to infect.

Er, no. That is almost wholly wrong.

Firstly, as far as I know, all local authority recycling plants use
high temperature composting, which will destroy much tougher organisms
than blight, even if blight transmitted through dead material (which,
in the UK, it does not). In fact, I believe that there are some
regulations that require them to, because of pathogens that often
occur in food and are harmless to humans.

Secondly, blight does NOT need wet leaves to infect, but high
humidity - not watering may have a secondary effect, but no more.
Even if it did need wet leaves, almost all leaves that close to
the ground are wet in the UK each morning, from the dew, and you
can't stop that.

Thirdly, removing blighted material is of marginal benefit, anyway,
as it overwinters in a large number of common plants and weeds, and
transfers by the wind. Yes, it's worth doing, but it won't make
much difference; spraying with Bordeaux mixture at the right time
will.


Regards,
Nick Maclaren.