Whitefly? in the GH. Help!

Do you keep it closed up during the day?

I think at this time of year if you don't act fast they will multiply before your eyes.

You can use insects to eat them? Not sure what they are called?

Sticky tapes.

I would empty the greenhouse, wash all your plants. Keep the really infested ones outside.

Wash greenhouse thoroughly.

Fleece plants for a couple of nights outside?? What plants have you got in there?

No, open during the day mostly.  I've got peppers, tomatoes, aubs, chillies, beans, sweetcorn, cucurbits,  bedding etc. Hundreds of plants.  It looks like the insects like peppers and chillies best. I've blitzed the couple of plants I've noticed the bugs on but I expect I've missed some.  I'll have a look on line for bio warfare as opposed to chemical warfare and buy some sticky tapes although I dont see them flying about (yet) .Thanks Scarlet.  I'm pretty sure they're whitefly but they're very very tiny. I'm going to get a lens on them to see what the look like magnified.
I'm daunted about emptying and washing the gh