[Ellie May]

Yes, the less the better.
Some mosquitoes carry heartworm and they inject it into your dog when biting.
To kill heartworm larva in your dog after mosquitoes have injected it, you have to use a heartworm med. This is absolutely necessary for most dogs in most areas. To deter mosquitoes K9 Advantix is supposed to work but flea/tick preventatives are really overused in my opinion. Tick bites may be a concern in your area because of Lyme's Disease. I would look into that.