Yes, Demon WP Insecticide is labeled for wasps. It will be effective for the control and erradication of wasps, as long as the wasps come in contact with the product.
Demon WP Insecticide needs to be used within 24 hours of mixing with water. In the original envelope it has a 5 year shelf life if kept out of extreme temperatures and direct sunlight.
Demon WP Insecticide are usually not removed after application so that it can continue to kill insects for up to 90 days. It is best to leave it there as long as there is activity.
Depending on the size and health of the fly and the amount of Demon WP it contacts, it generally would take anywhere from a few minutes to several hours for an insect like a fly to die after contacting an area treated with Demon WP. For a very quick kill for flying insects, we recommend Maxforce Fly Spot Bait or Alpine Pressurized Fly Bait.
As long as the product label instructions are followed and the product is only applied to places indicated on the label, the product should not be harmful to humans or pets.