Bug zappers are great for eliminating flying insects, but do they really work? Well it depends what you are using them for. If you are using them to significantly reduce the insect population of your yard then they are amazing.
If you are using them to only eliminate biting bugs they are not as effective without an attractant.
According to Alberto Broce, a professor of entomology, “zappers only kill a small percentage of insects that are annoying or damaging to human health.”
The word annoying is quite subjective, I personally find any flying insect to be annoying especially when it keeps landing in my sitting area and flying around me constantly. In this case a bug zapper works like a charm. If you want it it to truly be effective against mosquitoes you will need to use an attractant with it.