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Mosquitoe Control

Posted on Wednesday, September 5, 2012 at 4:00 am

Stephanie Romelczyk

West Nile Virus (WNV) has been making headlines across the country lately.  Most of the human cases reported (75 percent) have been from five states: Texas, Mississippi, Louisiana, South Dakota and Oklahoma.  Although relatively few cases of WNV have been reported in Virginia, now is a good time to talk about preventing mosquito bites.

Mosquitoes are most active between dusk and dawn.  During this time, be extra careful about protecting yourself and children against bites.  If possible, wear long-sleeves, long pants, and socks when outside.  Sometimes mosquitoes can bite through thin clothing, so consider spraying clothes with an insect repellent containing permethrin or DEET, especially if you spend a considerable amount of time outside.  Repellents containing the active ingredient permethrin should not be applied directly to the skin.  Be sure to read and follow all instructions listed on the repellent’s label.

When choosing an insect repellent, use one that is appropriate for the length of time you will be outside.  The Centers for Disease Control and Prevention (CDC) recommends:

Brief (1-2 hours): <10 percent DEET, <10 percent picaridin, <10 percent IR3535

Moderate (2-4 hours): ~15 percent DEET, ~15 percent picaridin/KBR 3023, ~30 percent oil of lemon eucalyptus/PMD, ~15 percent IR3535

Extended (5-8 hours): ~20-50 percent DEET

A product containing 20-50 percent DEET is recommended to protect against tick bites and would be a good choice if you are in an area with both mosquitoes and ticks.  Do not use products with more than 30 percent DEET on children under 12.

In addition to protecting yourself from mosquito bites when outdoors, do an inspection of your property to identify and control mosquito breeding sites.  Mosquitoes lay eggs in standing water, so here are some tips for preventing breeding sites around the house:

– Turn over or remove containers around your house where water collects – this includes old tires, toys, and buckets.

– Treat decorative ponds with products containing Bacillus thuringiensis israelensis – never treat moving water, such as streams, creeks, or rivers.  Also, farm ponds usually do not pose a major mosquito problem because most ponds have a wide variety of predatory insects and fish that feed on mosquito larva.

– Dump excess water from flower pot saucers.

– Flush water out of bird baths at least twice weekly.

– Cover or drain unused swimming pools.

– Keep rain gutters clean of debris so water will drain.

– Correct drainage problems in your yard so that rainwater will not collect in low lying areas.

Keep in mind that mosquitoes don’t follow property lines.  A community-wide effort is often needed to keep mosquitoes at a tolerable level – work with your neighbors to make the whole neighborhood a less desirable breeding ground.  For more information on West Nile Virus, refer to the CDC website: http://www.cdc.gov/ncidod/dvbid/westnile/index.htm and for more information regarding mosquito control, reference NCSU Insect Note ENT/rsc-6: Mosquito Control Around the Home and in Communities or contact my office at 493-8924.


Stephanie Romelczyk is the Agriculture and Natural Resources Agent for Virginia Cooperative Extension in Westmoreland County.