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Home » Announcements » Announcements CCHOA » Mosquito Activity at Coronado Cays Information


Mosquito Activity at Coronado Cays Information

There are multiple types of mosquitoes that can affect Coronado Cays residents such as:
.     Aedes aegypti
These mosquitoes are considered backyard/small container breeders. So think plant saucers, rain barrels, or small yard drains. They can be day time biters and are aggressive. They would most likely require individual inspections at private properties to locate the source.
2.     Culex quinquefasciatus
These are one of the most common species of mosquitoes and can be found in numerous breeding sources such as small containers but also ponds, rivers, green pools, underground storm drains etc. They are not as aggressive as the Aedes mosquito and usually don’t bite during the day.
3.     Aedes taeniorhynchus
The black marsh mosquito that is most likely causing the sudden increase of activity in the area currently. They are also aggressive, day time biters.To simplify as much as I can, This area north of the Coronado Bay Rd. revolves around dynamic marsh conditions that depends on the high tide. So if the high tide reaches over 6 ft. – 7ft. continuous water exchange occurs on average for about 5-7days about every two weeks and then dries out for a week or so and repeats the cycle. So this area gets treated with a larvicide that targets and kills the mosquito larvae before they can hatch into an adult mosquito. Because of that constant water exchange, occasionally, our product possibly does not penetrate the area long enough to kill the larvae before they can hatch off. There are other possible variables that could affect the efficacy of our product but for the most part we can usually achieve a 90%+ kill rate. Currently, there might have been a lesser kill rate that allowed a higher number of mosquitos to hatch off and enough to bother the Coronado Cays residents. The bad news is we can’t do anything about the current hatch of adult mosquitoes. We currently do not use adulticide (a spray that kills adult mosquitoes) withing the Vector Control Program to kill marsh mosquitoes. The good news is that they shouldn’t live long and decrease over the time of the next week or so. Other good news is that they are not a primary vector of major concern, however, we do consider them a localized pest and I can deeply sympathize with the residents for getting aggressive, itchy day time bites. This is why I will closely monitor the next high tide to prevent another hatch off.

Pictures below is the marsh area of concern highlighted in yellow.


Gillian McDivitt

Vector Control Technician

Department of Environmental Health and Quality