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?

--
David in Normandy.
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