YUK! What are these ?

Black fly?

Yes they're black fly as Cammomile said.

I'm no expert but there are some great people on this site with a great deal of knowledge and experience. I only know this as I have had to deal with the little critters myself.

There are are several things you can try.

1. Potassium-salt soap that can be bought at most of the gardening centres.
2. Spray with diluted washing up liquid.
3. Pre-planting with plants the black fly hates- tagetes [spelling?] calendula, poached egg plnt, morning glory. [probably too late for this]

I prefer the washing up liquid in water but this must be done regularly.

Good Luck

Thanks!. Think I'll try washing up liquid first.

I used this system many years ago with great success. It may be a bit of a palaver but I was trying to keep things chemical free at the time and an old boy told me about the toxicity of Rhubarb leaves. If you can be bothered.....

Cut 450g (1lb) rhubarb leaves, place in an old saucepan (the oxalic acid may damage one that you still use) with 1.1 litres (2pt) water and boil for half an hour, topping up as necessary. When cool, add 1 dessertspoon of soap flakes dissolved in 275ml (1/2pt) warm water. This acts as the wetting agent when added to the strained rhubarb liquid. Stir the mixture thoroughly and use undiluted as a spray. Rhubarb leaves are quite toxic so be careful to keep this away from children and pets.

Spray healthy plants as prevention and affected plants to help remove infestations.

I couldn't remember the exact recipe so got it from this website which has lots of alternative treatments as well as conventional ones. www.pan-uk.org/Projects/Local/alt~dir/aphids.htm