I have read that they are beneficial insects to have. However, we get anywhere between 5-20 hornets nests built on our house and barn each year and the kids end up getting stung. What is good about hornets? Is there a way to get them to build there nests in desirable areas? Is there an imbalance on my property that is leading to such a large amount of hornets?
I suppose you will need to figure out what species you have... what that species eats... figure out where Your local hornet population is getting it's food... and then make the decision of what to do. They may be benefitting you by eating larvae that are eating your crops. Keeping populations in check.
If you wipe out the hornets... is your crop going to get eaten alive?
I had a very small wasp nest show up next to my garden last year. The broccoli in my garden was getting eaten alive by white cabbage butterfly larvae at the time. I was happy to watch the wasp hovering around my plants on the hunt. I just kept my kids away unless I was standing there with them. A baseball cap has more than one use. However, if they just got to close I usually just blew on the flying bugs really hard and they would get the hint and fly away.
Hornets hunt and kill caterpillars, in particular.
Generally people and hornets should be able to coexist, although I know it is harder for kids to avoid the flapping and slapping that tends to bring on stings. You can wipe out a ground nest by covering the exit with a clear plastic or glass bowl. If they can see the sun, they never try burrowing out another way, they just keep bumping up against the barrier. Put some dirt all around the outside edge, so they can't crawl out.
Getting a good identification of which kind of hornet it is will make a difference. There are many kinds and they eat different things and have varying levels of aggressiveness.
I love the cycles of predator-prey like the wasps that lay eggs in the tomato hornworms. However, the bee-wasp-hornets that make nests on my house and barn and shed and camper and tractor and everything else upon which the sun shines...well I wish they would go away. I didn't used to mind them, a sting every so often is no big deal, but now my husband and I have both been dying often enough that we are allergic. I had two close calls in recent times when I was alone caring for small children and got stung and started to swell up in important places like my throat!. It was scary and dangerous.
The traps I have tried have not helped at all, I think they were meant for other members of the bee family. Keeping things out of the sun helps keep them from nesting. But I can't get the house or the barn etc out of the sun! I have heard that if other members of the api family move in they will move out, but have not figured out how to make this happen. Perhaps mason bees are an answer? I wish I had better answers for you, and I'm hoping someone else does! I am all for diversity of course but I'm still wishing for less aggressive bees.