Juno from Tallahassee Fl. writes
Demon WP will last for about 30 days or more once applied from a sprayer. Once mixed, Demon WP should be applied and none kept if your sprayer as a mix. Since Demon WP is a wettable powder, if you store it in your sprayer for more than a week it will start to settle and can clog the hose or nozzles to your spray device. You should always only mix what you can apply right then.
Answer last updated on: 08/21/2011