Wasps.
Last years the guys at work found a wasp nest in the yard in this large plastic container. There were fucking loads of them. So this is what I did. I got a box of bangers out of my van (For the young folk who do not know what a banger is, google it. they got banned years ago. I still have some, do not ask why) Anyway 3 lit bangers thrown into the container, big bang flash, no more wasps. Simple.