White Fly

Provado Ultimate Bug Killer is good stuff.The whitefly has a 3 week life cycle!So spraying is almost a weekly thing to keep them in check.Home made,you can try your own Horticultural Oil mix, vegetable oil mixed with ordinary soap.Prevention might be to cover plants with garden fleece to keep them off,but you have to bury the edges otherwise they will sneak under! Frost wont do much,but adult flies are killed off by heavy rain,so you can also blast plants with a hose on a regular basis.Careful how you dispose of infested plants or you will end up spreading the whitefly elsewhere. They are very resilient and probably here to stay,so keep trying and see what works best.

Thankyou very much darryluk. I will try to get rid of the little devils otherwise I shall lose my enthusiasm for growing my veg.I have swarms of them every time I move a leaf .