David WE Roberts wrote:
The butternut squash in the back garden is infested with blackfly.
We have put a couple of ladybirds on it in the past, and today I noted
two ladybirds on the plant wandering about in a slightly dazed fashion
(although one was a 'black with red dots' so not one we had introduced).
However given the number of blackfly a couple of ladybirds are as likely
to have a visible impact on the total numbers as a small child with a
teaspoon is on ten tons of jellybeans.

I've left it alone thus far as I expected natural predators to multiply
and feed off the enormous area of free food.
However this has not happened.

I've just given roughly half the plant a spray with soapy water to see
if that will clear the leaves and stems.
I've left the other half just to see how much difference the soapy water
makes.
No other plant in the garden seems to be infested, and certainly not to
this level.

Any idea how long the soapy water takes to act, and if the blackfly drop
off or just die 'in situ'?
And if so, how do you tell that it is working??

Cheers

Dave R

I've found a wet paintbrush to be as effective as anything, if a little
time consuming :-)