Hi you can buy sticky fly traps that you hang up . these will attract the flying white fly. dispose of your plants when they have finished, then clean your greenhouse thoroughly, scrub with Jeyes fluid in all nooks and crannies. If you can find a 'smoke' bomb for the purpose they are good too.
next season hang the sticky trap up at the beginning of the growing season.

Also, over ripe & decaying fruit will also attract flies

Different from whiteflies, though, Bathgate--those are fruit flies of some kind.
Taid, thorough and frequent spraying of the foliage with organic dish soap solution, usually 15 ml per liter of water, will cut the whitefly numbers down to where the sticky traps can get ahead of them.

I know fruit flies and white flies are different. I took 7th grade biology too. :)

Sorry! :[

Its ok lol i was just saying what could draw other types of flies. They are a highly specialized & necessary part of our ecosystem, the decomposers.

Thanks everyone for your replies, I will thoroughly clean it at end of season, and will have fly traps in there.

These white fly have only been noticeable these last few weeks.

Thanks everyone. John.

The idea of using any insecticidal bomb makes me cringe. I had a friend who used one in his greenhouse. He must of taken a couple of breaths of the stuff, collapsed and did not survive. He was alone at the time. If you do intend to use a bomb I would advise that you have someone on the outside watching just in case you rapidly develop a pulmonary reaction to the vapor.

Wow! What a brutal lesson

the smoke ones if still available in the uk were lit on a long fuse and the bomb burned slowly like a candle. Not aware of fatalities but I have never used them. Sorry to hear about your friend though.

Hi, you can get a non chemical garlic candle, which isn't harmful to beneficial insects such as ladybirds, or to humans, here's a link for you.
www.greengardener.co.uk/product.asp?id_pc=13&cat=25
Derek.