In article ,
Paul Luton wrote:
A few weeks ago my block of broad beans (Sutton) was looking fine.
Just as they came into flower blackfly descended right amongst the
flowers (looked at sprays but they warn against spraying flowers) and by
yesterday there were no viable pods.
I have tried cutting back to the roots in the hope of new shoots.
Next year I will try removing the tops after a few flowers have opened.

I think that you made a mistake.

You CAN spray if you use a non-toxic one. You won't get those in a
garden centre.

I use Savona (horticultural liquid soap, available from Tuckers),
Green Gardener have some rape-seed oil stuff (sticky, don't spray
onto windows), or could can make up a slightly stronger than normal
washing-up solution of washing-up liquid with a squirt of methylated
spirits.

When the blackfly start to hit, soak the plants with infestations
using a hand sprayer. Don't worry about the other beans. Repeat as
needed. If the ladybirds etc. seem to be controlling the blackfly,
don't spray those plants - what you are trying to do is stop the
explosive infestation for long enough for the parasites to get a
grip. This year, I have had to spray only a few plants only a few
times.


Regards,
Nick Maclaren.