Mosquito Activity on the Rise

— Written By
Storm water trapped by to prevent running into river

Impounded storm water can become a mosquito breeding site (M. Waldvogel – NC State University)

Memorial Day weekend is often the signal to fire up the grills. However, the previous week’s heavy rains in many areas of the state have also fired up mosquitoes who aren’t practicing “social distancing” as they look for a meal.

Areas such as the one shown here which are designed to prevent run-off into nearby rivers may hold stagnating water for weeks; plenty of time to generate a generation of mosquitoes.

Mosquito larvae in water trapped in a tarp.

Water trapped in a tarp is filled with mosquito larvae (M. Waldvogel – NC State)

Regardless of whether you plan to treat for mosquitoes, whether that’s using a backpack mister against adults or Mosquito Dunks dropped into pools of larvae-filled stagnant water, NOW is the time to get some outdoor exercise and see where these water-filled areas are located and try to eliminate them as best we can. Aside from pooled water in or near our yards, there are many other areas and objects that can serve as mosquito breeding sites.

As I have mentioned previously, an unpublished study in the 1980s led by Dr. Charles Apperson (professor emeritus in NC State University’s Entomology & Plant Pathology Department) looked at where Asian tiger mosquitos were breeding in typical residential settings in New Hanover County. Here’s what they found:

Containers used as breeding sites by Asian tiger mosquitoes
Source No. Positive Total Examined Percent Positive
Miscellaneous containers 92 148 62.2%
Buckets 24 39 61.5%
Plant dishes 33 48 68.8%
Tree holes 7 8 85.5%
Plastic film (tarps) 8 11 72.7%
Bird baths 8 27 29.6%
Tires 11 20 55.0%
Toys 8 14 57.1%

This serves as a good reminder that we are frequently the cause of our own mosquito problems and that “Tip & Toss” are still our first line of defense against mosquitoes.

Over the last few years, July has been the month where we see the first report of eastern equine encephalitis (EEE) impacting on horses in the state, most commonly in southeastern NC and typically with horses that were not vaccinated earlier in the year. EEE is often fatal in horses. One thing we can count on is that mosquito populations will continue to rise throughout the summer and into the early fall, particularly if we do get severe weather or possibly a hurricane and flooding. So, even if you’re behind in getting your horse vaccinated, talk to your veterinarian about what steps you should take now before the likelihood of the animal getting bit by an infected mosquito catches up with you. On the human side, the first cases of mosquito-borne disease such as  EEE, LaCrosse Encephalitis and West Nile Virus often begin to appear in June-July. So, as we all spend more time outdoors hiking, biking or  gardening (or removing those water and mosquito-filled objects), wear repellent!!  If you decide to treat your yard for mosquitoes, take time also to look on the other side of fence to make sure you’re not accidentally spraying your neighbor’s vegetable garden. Many of the commonly used mosquito products are not labeled for use on edible plants and may have restrictions on spraying plants (and weeds) that are in bloom or may have chemical drift onto them. Let your neighbors know about your plans in case they have taken up backyard beekeeping or the pets or children are frequently outside where the chemical can drift. Good communication makes for good neighbors~

For further information mosquitoes and repellents, see:

Mosquito Control Around Homes and In Communities

Insect Repellent Products