Sorry ChrisG, but I would never, ever put the sticky yellow fly catchers in the greenhouse. As allaboutliverpool says, those sticky traps catch the good guys as well as the bad. You might get some greenfly stuck to them, but you will also get hoverflies, bees, lacewings. etc. On balance, I would not use them. For what bad bugs you catch, you are likely to catch more good guys.
valmarg