Back to Top

Delta Journal
by Bob Thomas

“Ouch! That mosquito hurt!” Sound familiar? Such an exclamation usually indicates the periodic arrival of the salt marsh mosquito (Aedes sollicitans). These fellows are dusky brown with a grey patch on their sides and they have a white ring around their proboscis and several around their legs. It is bad enough that their bites are immediately annoying, but, unlike other mosquitoes which become active at night or on overcast days, salt marsh mosquitoes will bite throughout sunny days. They are strong fliers, so head-winds as high as 15 mph do not deter them.

This species’ natural history gives us a clue about its periodicity and, interestingly, how humans are causing an increase in numbers of such an aggravating pest. Salt marsh mosquitoes lay their eggs on dry ground that floods occasionally. Eggs hatch within a few minutes of being immersed in water and development to adulthood requires less than a week. As the adults emerge, they migrate up to 40 miles. The most prolific breeding grounds in our vicinity are to the east and southeast. That is why we occasionally have sudden infestations of salt marsh mosquitoes associated with recent rain following a dry spell, coupled with southeastern winds.

An important point is that standing water is not producing our worst pests. They are increasing in numbers and frequency of invasions as more land is drained for development and spoil areas are produced and allowed to intermittently hold water. The simple answer to this human problem is to leave wetlands wet!