In article ,
RedAcer wrote:
On 22/10/16 12:47, Janet wrote:

My experience (in Scotland) is the same. I've never seen blackly on
runner or french beans ; broadbeans so infested I don't bother growing
them any more.

Do you cut the top 6^" off each plant as soon as the first bean sets on
the plant? I've had great success doing this. You do get small colonies
on lower leaves occasionally, which are easily removed by rubbing with
your fingers every few days during the worst times.

I pinch out the tops, leaving 4 layers of flowers, mainly to eat them,
but it does little good against blackfly. What I do notice is that
the blackfly don't leave their winter hosts until the weather starts
to warm up, so early sowings are fairly OK and later ones less so.
I can easily believe that the problem is very location-dependent.

I also spray the hell out of infestations with soft soap until the
beans have set solidly, which is almost essential, or the beans
aren't worth eating. Soft soap works as well as anything, and is
completely non-toxic (including to the plants).


Regards,
Nick Maclaren.