Critters: Blood Suckers

It’s that time of year again. The time of year when spending a few hours outside around dawn or dusk inevitably brings annoying, itchy bites from bloodsucking mosquitos. But does it somehow seem worse lately? Well, it just might be. Why you ask? And what can we do about it? Well, let’s start with the why. In two words, the why is climate change. Certain species of mosquito like Asian tiger mosquitos (Aedes albopictus) and yellow fever mosquito (Aedes aegypi), which were historically limited to tropical regions like Central America, sub-Saharan Africa, and the South Pacific have been expanding their range into sub-tropical and temperate regions as our climate warms. Tropical mosquitos and the diseases they carry like Malaria, Zika, West Nile Virus, and Dengue Fever have become a concern for cities around the world from Del Mar to Paris to D.C.


On top of the warmer air and water temperatures, these species which need only five to ten days of standing water to breed and complete their development from larvae to flying adult mosquitos are getting more opportunities with out-of-season rain in our region like the recent storms from Hurricane Hilary. Normally our rainfall is limited to the winter (non-breeding months) and less standing water remains when the mosquitos arrive on their migration (yes mosquitos migrate like butterflies and many other insects). Out of season (summer) rain leaves puddles and other standing water at exactly the worst time as far as mosquito breeding is concerned.

Photo by Jonathan Appelbaum.

So it’s getting warmer and occasionally wetter. On the surface it’s pretty bad news for our mosquito problems I’m sorry to say. However, you don’t have to resign yourself to a summer of itching and scratching. You’re not totally helpless.


In your own yard you can do a few things to fight the bite. First, you can perform a quick inspection and make sure that you don’t have any puddles or standing water inside of any empty flowerpots, buckets, and even tree hollows. Avoid over-irrigation that can leave puddles for mosquitos to breed in. Clean the debris out of your gutters so they don’t get blocked and collect stagnant water for mosquitos to breed in. If you have fountains or other water features, make sure pumps are in good working order and provide sufficient circulation or agitation to disrupt mosquito breeding.


Finally, if you have rain tanks make sure all overflows are screened to keep adult mosquitos from flying in and laying eggs. Beyond the edge of your yard, its going to be up to your neighbors and public agencies. Remind your neighbors and HOAs to avoid overirrigation and to maintain any fountains, ponds, and water features located in community spaces. Finally, report mosquito activity to the County of San Diego Department of Environmental Health (DEH) Vector Control Program at