I get a call, at least once a week on average, asking what someone can put in their pump up sprayer that will work. The answer is: nothing.
The key to eliminating mosquitoes is thoroughness. Pump up sprayers do not cover enough area to be very good at repelling mosquitoes. That is why, on the cheap end, we recommend hose end sprayers. On the high-end, we recommend the SR200 by Stihl (about $395) which will cover the ground thoroughly. This is the unit most of the professionals use.
When I am testing repellents, whether mine or someone else’s, I spray myself head to foot, including clothes. The only thing I don’t spry is my eyeballs. Well, the mosquitoes attack my eyeballs! They can find that one small area where I haven’t sprayed!
So, combine that with the mosquito’s excellent ability to hide for survival and you can see why it is important to cover everything when trying to push mosquitoes out of the area. A good hose-end sprayer is only about $11 (Chameleon is a good one.) If you don’t like dragging a hose around, try using granules in some of the tougher places along with the hose end spray.
If you leave a hole or a gap, they will find it. If you don’t spray under the furniture or up in the gutters, that is where they will hide!