During the rainy season of April-November the mosquitoes in Marbella, Panama can be quite persistent.
There is a sewerage / stream channel running through a part of Marbella where I first lived, which attracts them and the larger amount of backyard pools is also an attraction. However, I've always sprayed on some insect repellant and if needs be a light a mosquitoes coil and happily spent the evening outside by the pool.
This year they sprayed the streets regularly to help kill off any mosquitoes, as Dengue fever had its run (outside of the City, mainly other parts of Central America), so it's good to know they were proactive in attempting to prevent the risk.
I've never met anyone in Panama who's had Dengue. Other insects haven't worried me.