The gardening magazines all seem to recommend using yellow sticky traps, largely it seems to identify a problem with something like whitefly. I used them one year but never again, because they caught all the beneficial insects, and it's impossible to rescue them once they are stuck. So I had bees, hoverflies, ladybirds, lacewings and so on which I had to squash to put them out of their misery. The traps went into the bin and I've raged against them ever since. I even sent a letter to one of the gardening mags about them but of course they didn't print it, as it would put some advertisers noses out of joint.
Has anyone else tried them?