"David in Normandy" wrote in message
. fr...
As everyone has warned black fly have appeared on my broad beans. This is
the first year I've grown them. They've not even set any flowers yet and
several plants have colonies of black fly at the growing tip.

Knowing how useful washing up liquid is against aphids I've tried spraying
them with a relatively strong solution of washing up liquid in full
sunshine. After a few hours the results look promising, sort of. The
leaves below look like they've been splashed with black ink, presumably
from the black flies. They aren't moving any more. It will probably be an
ongoing process to spray them like this but if it works it is a cheap and
relatively organic way of dealing with the pest.

Anyone else tried this against black fly? Was it successful?

--
I tried it last year. It killed the plants I used it on. It was a cheap
brand of washing-up liquid but, according to an experienced gardener, I
should have used Fairy Liquid.

KC