Hi Jenny,

The short answer is: anything vegetable or plant based.

There's a good article on Ecocharlie with a variety of suggestions:

http://www.ecocharlie.co.uk/blog/index.php/2010/03/08/plant-pests-%E2%80%93-ten-top-organic-solutions

The best options might well be a vegetable-based washing up liquid solution - something like Ecover is ideal - or one of the plant-based home made sprays. I like the idea of using the natural defences of one plant (like Chilli, Garlic or Rhubarb) to protect another too.

Many thanks, I'll try the Ecover first.