I thought we had a swarm of wasps in the conservatory today and have used a whole can of fly spray trying to eliminate them. Dh just home and has examined them and reliably informs me they are hover flies but how do I get rid of them? There are hundreds of them!
we've also had quite a few hover flies in our conservatory although not hundreds. Rather than fly spray, I got a Rentokil Fly Killer pen. Its like a marker pen & you just draw on your windows - it doesn't leave any mark & seems to kill flies on contact (you get a nice pile on your window sill - yuk). Don;t know how to prevent them in the first place other than trying citronella candles etc.
Champs, hoverflies are a nuisance in that they love bright colours and will come and sit on you, but they are harmless, promise. We have a cloud of them under our pergola, making an annoying tic-tic-tic sound as they bump against the roof, but their babies are eating every aphid in sight, as Throckenholt says, so they are welcome guests in our garden (unlike wasps who deserve to die die DIE).