Because of all the news you are now hearing about the West Nile Virus and the fact that, fortunately, we have recently received some much-needed rainfall, this column provides me the opportunity to share some very important information and recommendations with you. Whether you are a farmer, a homeowner, or just a casual reader, I would encourage you to do what you can to prevent possible health problems for you, your family, or your friends.

Because of the extended drought this summer, we have experienced less mosquito problems than normal. Naturally, there have been some mosquitoes around this summer, and some people have experienced some rather severe problems with them, but for the most part, mosquitoes are not nearly as bad as they would have been if we had received a normal amount of rainfall.

So often I have heard the expression during the winter, "I'm so glad to see all this snow and ice, because it will get rid of some of the insects." This may be true for some insects but not for mosquitoes. Mosquitoes can survive very well in Robeson County during severe winters, just as they do in Alaska.

Droughts during the summer do more to reduce mosquito populations than does freezing weather during the winter. Lack of rainfall reduces the amount of standing water in mud holes, swamps, old tires, discarded pots and pans, and other places where mosquitoes may breed. Without water, these insects cannot complete their reproduction cycle.

With the recent showers we have had, we are likely to see sharp increases in Asian tiger mosquitoes. These are the mosquitoes that are the carriers for the West Nile Virus. While these rains were not enough to put a dent in our drought, they were more than adequate to provide breeding grounds for mosquitoes.

Because of water restrictions in many communities, and in an effort to reduce the use of municipal water, many residents are collecting rainwater for watering flowers and other plants. The people responsible for monitoring for the West Nile Virus have been doing backyard inspections to determine the mosquito population as well as trying to determine factors that may cause mosquito populations to either increase or decrease. Inspections last week found many buckets filled with rainwater at a fairly large number of residences. The potential mosquito problems resulting from this practice are obvious. Another very significant but often overlooked production site are the receptacles that are placed under potted plants to collect water. Over 50 percent of the plant pot receptacles that were inspected contained mosquito larvae or pupae. While this may conflict with people's need to water plants, it is preferable that water not be allowed to remain in the dishes beneath plants.

We all must understand that virtually any standing water source is a potential mosquito breeding ground and needs to be removed whenever possible. Ordinary window screening properly placed over water-collecting buckets and barrels will keep mosquitoes out. Many of the large barrels that are being sold by Extension Centers in some counties for collecting rainwater or those available from garden centers are usually equipped with such screening.

Another approach to eliminating mosquitoes in certain breeding sites is to use the "Mosquito Dunks," the donut-like tablets that contain Bti (Bacillus thuringiensis israelensis). This product kills mosquitoes, fungus gnats, and a few other fly species. There is also a granular form of this product called "Mosquito Bits." As with any pesticide, the instructions for using the products are on their labels. These products are not intended for use in bowls or buckets used as drinking bowls for pets.

I have received quite a few calls from people asking about what they can spray for mosquitoes. Many have asked about the electric and gasoline-powered fogging machines that are available in retail stores. As with any do-it-yourself pest control, results with these devices may be far less than expected. Fogging your yard does help reduce the number of adult mosquitoes. However, it has little, if any, impact on the source of the infestation which is the breeding areas. This is especially true in many residential areas where Asian tiger mosquitoes are most prevalent.

If you decide to purchase and use one of these devices, I would like to urge you to use extreme caution. You should wear appropriate safety equipment such as long-sleeved shirts and pants, goggles, and a respirator in order to avoid contacting or inhaling these chemicals. Never direct the insecticidal fog into the wind, and pay particular attention to your surroundings, particularly in residential neighborhoods where adjoining properties and people are in closer proximity.

Spraying lawns and shrubs will also kill resting mosquitoes, but again, it is not likely to have a tremendous impact overall. Mosquitoes don't understand the concept of property lines, so they're just as inclined to fly into untreated areas in search of a good meal, and this meal may be you. Mosquito control, chemical or nonchemical, has to be a community effort in order to be successful.

I have also received a few calls about the effectiveness of the mosquito trapping devices that are being sold in many retail stores and over the Internet. Research has shown that these devices will attract many species of mosquitoes but not all species. There is a lack of scientifically based data to show that these devices will actually have any impact in reducing mosquito populations. More importantly, it is unknown at this time if these devices will actually provide the type of protection that the public expects. Those people wanting to spend money for these devices may get more comfort from the attempt to do something than in actually reducing mosquito populations. At this time, these devices are not being recommended as a primary means of preventing mosquito bites or the potential of mosquito-borne diseases.

If you have access to the Internet, you might want to visit http://www.ces.ncsu.edu/depts/ent/notes/Urban/repel.htm for more information about insect repellant products. As always, don't hesitate calling your Extension Center at 910-671-3276 for more information.

If you or your children are going to be outside, especially late afternoon when the mosquitoes are most active, you are encouraged to use the mosquito repellants containing DEET. The use of this product should be limited on very small children.

Most of all, eliminate the breeding area for mosquitoes, and urge your friends and neighbors to do the same.

• Check your property, and eliminate as much as possible all sources for standing water.
• Properly cover buckets or barrels used for rainwater collection.
• Empty and clean bird baths and pet watering containers frequently.

Recommendations for the use of chemicals are included in this article as a convenience to the reader. The use of brand names and any listing of commercial products or services does not imply endorsement by North Carolina State University, North Carolina A and T State University, or North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical. For assistance, contact the Cooperative Extension Service in your county.

E-mail address: Everett_Davis@ncsu.edu

Mailing Address:
P. O. Box 2280
Lumberton, NC 28359-2280

Phone: 910-671-3276
Fax: 910-671-6278

Date Created 9/13/02