It is your timing that might be off!
3 total sprays!
First one say tomorrow,
Second spray a week to ten days later.
Third spray a week to ten days after that.
If the gap is too large for example between 1 and 2, they could hatch the day after you spray, live, mate and lay eggs before you spray again. Their life spans are very short. You must spray according to their life cycle, not according to your schedule. 50-50 water and Isopropyl alcohol and a couple of drops of dish soap in a quart spray bottle.