by David Moore
Manager of Technical Services and Board Certified Entomologist
with contributions by Eric Smith, PhD, BCE
Unfortunately, we’re probably going to have lots of mosquitoes again this year. This is because the mild winter we had increased the overwintering survival rate and then we have been getting lots of rain. This usually means a bumper crop of mosquitoes. Here are a few things that you can do to reduce your risk of getting bitten.
AVOIDING MOSQUITO BITES
- When you go outside, use insect repellents; those containing DEET are recommended, but do not apply DEET under clothing.
- Be sure to read and follow the label directions. Some repellents should not be applied to children and children should never apply repellents, you should do the application.
- When you go outside, wear long sleeves and long pants; certain brands of clothing are pretreated with repellents such as permethrin, which provide additional protection.
- Avoid going outside during dawn and dusk; these are high mosquito activity times.
- Install or repair screens on windows and doors. If you have it, use air conditioning and keep the windows shut.
- Install self-closures on screen doors so they are only open for a very short time.
- Empty standing water from items outside your home such as the saucers under flowerpots, buckets, barrels, sprinkling cans, used glasses, empty soda/beer cans, etc.
Birdbaths and pet dishes
Replace the water at least weekly; mosquitoes usually go from egg to adult in about 10-14 days.
Either tightly cover them when not in use and check them for wigglers (immature mosquitoes) and empty and refill if found, or empty and refill the pool at least weekly. If you have the patience and time, you can remove the wigglers with a tea strainer or pet fish dip net.
- Make sure that they are free flowing and there is no debris or stagnate water present.
- Fill in any low areas in your yard where rainwater or irrigation water collects.
- If you have trees in your yard, keep branch crotches free of debris.
- If any of your trees have tree holes, empty them of water and debris once a week; using a kitchen/poultry baster is the easy way to remove the water.
Decks or patios
- Use a water misting fan that blows fine water droplets in its breeze; they cost about $200 to $250. Mosquitoes are not strong fliers and avoid breezes. Also, the water droplets act like a rain of bullets being shot at them, which they do not like.
- The evaporating water mist will also lower the temperature by about 10° which will let you enjoy your time outside even more.
DO FOGGERS REALLY WORK?
The short answer is somewhat. And you ask, why? That’s because foggers only affect the mosquitoes that their mist droplets directly impact. This means:
- Much of the fog released will be carried off in the wind, never contacting mosquitoes.
- Foggers should be used only when there is very little wind (less than about 3 mph).
- The really bad bitters (members of the genus Culex) rest up in the upper parts of trees where the mist of foggers typically doesn’t/can’t reach.
- If directed from below towards the undersides of plant leaves where mosquitoes typically rest, then the fogger’s mist will contact and kill those mosquitoes.
- Typically, yard foggers contain materials that do not remain active for very long to help protect the environment. That is, they have a very short residual action.
WHAT ABOUT ZAPPERS?
These have 2 basic problems:
- First, they attract many different kinds of insects to where they are located via their UV light, insects that would not otherwise be there. This means more nuisance insects.
- Analysis of zapper trap catch has shown that they attract very few biting flies such as mosquitoes, less than 1%. However, they do attract and kill an estimated billions of harmless and beneficial insects each year, those that feed on pest insects, that process dead carrion, that process dead plant materials, etc.
- Only the very expensive zappers (about $1,200-3,500) that release carbon dioxide show promise depending on the situation. Mosquitoes follow the carbon dioxide they release from downwind, so their drawing power is somewhat directional and limited. Also, wind can scatter and dilute the concentration of the carbon dioxide they release, which decreases their attractiveness and effectiveness.
DO CITRONELLA CANDLES AND TORCHES HELP?
Yes, but … These help to reduce the number of mosquitoes in the immediate area or for very short distances. Again, if there is a wind, their effectiveness will be reduced.