Take the time to learn that there is not a "cure all" for every pest at every stage of it's life cycle. Some won't work if it's going to rain. Some don't work well if it's too hot, etc. You shouldn't use Sevin unless you know it will work for the insect you are trying to get rid of and in most cases there are less harsh chemicals you can use than Sevin. Pest management is complex, if you wish to use chemical products, do so responsibly which goes further than reading the label. If you want to learn, a good place to start is here: Integrated Pest Management This lecture is presented in two parts. Each part is 90-minutes in length. Recorded in Sacramento County in California's Sacramento Valley, this lecture is by Mary Louise Flint, Ph.D., Director, IPM Education and Publications, UC Statewide IPM Project and Extension Entomologist & Cooperative Extension Specialist. Education: B.S. Plant Science, University of California, Davis Ph.D. Entomology, University of California, Berkeley Appointment: 100% Cooperative Extension Research Interests: Integrated pest management of landscape, agricultural and garden pests; biological control of arthropod pests; alternatives to pesticides; adoption of alternative practices by practitioners; innovative delivery of pest management information. Topics discussed in the Integrated Pest Management Lecture: * IPM references and resources * Preventing pest problems * Natural common enemies * Making less toxic pesticide choices * Controlling aphids, scales, caterpillars, coddling moths, tree borers, snails and slugs, and lawn insects. You can watch the programs now online: Just make sure you have Real Player installed or download it free. Integrated Pest Management Part1 90 minutes Integrated Pest Management Part 2 90 minutes You'll want to bookmark the following link to Professor Flint's Lab Research on: Controlling Pests in Gardens and Landscapes: Vegetables and Melons I promise you'll learn one or two things to put in your gardening bag of pest management arsenals. ;) Take the time to learn that there is not a "cure all" for every pest at every stage of it's life cycle. Some won't work if it's going to rain. Some don't work well if it's too hot, etc. Pest management is complex, if you wish to use chemical products, do so responsibly which goes further than reading the label. If you want to learn, a good place to start is here: Integrated Pest Management This lecture is presented in two parts. Each part is 90-minutes in length. Recorded in Sacramento County in California's Sacramento Valley, this lecture is by Mary Louise Flint, Ph.D., Director, IPM Education and Publications, UC Statewide IPM Project and Extension Entomologist & Cooperative Extension Specialist. Education: B.S. Plant Science, University of California, Davis Ph.D. Entomology, University of California, Berkeley Appointment: 100% Cooperative Extension Research Interests: Integrated pest management of landscape, agricultural and garden pests; biological control of arthropod pests; alternatives to pesticides; adoption of alternative practices by practitioners; innovative delivery of pest management information. Topics discussed in the Integrated Pest Management Lecture: * IPM references and resources * Preventing pest problems * Natural common enemies * Making less toxic pesticide choices * Controlling aphids, scales, caterpillars, coddling moths, tree borers, snails and slugs, and lawn insects. You can watch the programs now online: Just make sure you have Real Player installed or download it free. Integrated Pest Management Part1 90 minutes Integrated Pest Management Part 2 90 minutes You'll want to bookmark the following link to Professor Flint's Lab Research on: Controlling Pests in Gardens and Landscapes: Vegetables and Melons I promise you'll learn one or two things to put in your gardening bag of pest management arsenals. ;)

If they aren't acting aggressively like defending a nest and aren't particularly bothering you, why don't you just give it a couple of days and see what happens. I wonder if they are being attracted to water - if you are irrigating your lawn, or hunting some kind of insect present there. I've watched yellow jackets hunting crane fly larvae in my lawn when those begin to hatch, so a beneficial behavior rather than something to treat. I don't think I've seen anything in quite the numbers you describe though...let us know what happens.

I had to get rid of two wasp nests in my life. I didn't want a nest around my kids and myself so I couldn't leave it alone. The first time I hired professionals to do the job https://ajverminatorpestcontrol.com/wasp-pest-control-sunderland/. The second time, Ilearned the job from them and did it myself. I got some foaming wasp/hornet spray cans, and sprayed about 10-15 feet. I waited until a cooler night, and first thing in the morning got out there and sprayed the hell out of the nests--soaked them thoroughly. The cool night means they will not be very active in the morning, and since the nests are open like that, you will be able to kill them easily. Then remove the nest. That's it.

Well, none of our forty or so Trick or Treaters managed to get stung by my paper wasps. In fact, none of them were even aware that there were about 200 wasps a few yards away, and I'm pretty sure that none of those wasps ever took to the air. I built up some paper shields around the mob of wasps, so they wouldn't be conspicuous. I'm a little disappointed that no one even asked "Whatcha got up there behind the paper??" Had one asked that I could have said "Well, it's Halloween, so I get to scare you and freak you out right? There are a couple of platoons of stinging wasps up there, over your head, just waiting for you!". At which point the kids would run screaming from the house, and inform their fellow Trick or Treaters that our house must be avoided like the plague, thereby leaving us with a lot of candy. Yum. But that didn't happen. Sigh.