Anti mosquito laser turret

Hi,

I'm working on an anti mosquito laser turret.
tracking is working : https://youtu.be/EYmjTQUcmtg

Now I'm starting to play with servomotors.

I have some question regarding the laser :

Does it need to be focused? I saw a video from a 750mW laser pointer and at 20 meter the "dot" was 30cm wide :o

if my laser beam bouce on 3 mirror before hitting the target, does it reduce the beam power? I mean of course it will because there is no perfect mirror, but how much power loss are we talking about wit regular walmart grade mirrors?

Do any of you know what kind of laser would suit my needs? I have no idea of how much power I need to burn a mosquito, I intend to shoot up to 30 meters.

Thanks.