pico said:If Avid works for 28 days, then why do you have to spray 3 times 3 days apart to kill all life cycles?
I think you are thinking of Floramite that lasts up to 28 days. 1 spray, all dead.
I've never needed to spray them a second time with Avid...and most of the eggs never hatch after the spraying - the very few that do, die immediately after their first feeding. But the 28 days is the max persistance in an ideal environment that doesn't promote it's natural breakdown.
Never tried Floramite, but I've heard lots of good things about it - and some bad tho. What I read on a PDF from the manufacturer stated that it remained active on the plant for up to 12 months...maybe that was a longer duration version for particular uses?