Citronella? The Gulf Coast skeeters laugh in it's general direction (to misappropriate a John Cleese-ism).
The skeeters in south Texas (near the Gulf, where it's super humid, i.e., saturated air mass much of the time) are certainly capable of surviving in large numbers and of growing to significant size.
I.e., they are aggressive about getting their meal and procreating. The Asian Tigers... man... they are a true menace, what with being out a big fraction of the day looking for a bloodmeal.
Even a few are out during dry spells (we only had 0.06" of rain in May), probably sustained by the water held up in the storm drains.
But man, when it rains, a whole crop of the tiny yet very durable eggs, thusly nourished by mother nature's nectar (rain), will hatch and commence to feed within a day or two, and reproduce another batch of the tiny spreaders of the West Nile. Near pestilence I tell you.
Minnesota is supposed to be legendary for mosquito's, but I suspect it isn't any worse than the Gulf Coast. Cain't be.