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Residences, Structures and Communities |
As many people may know by now, birds infected with the West Nile Virus have been found in 12 counties in North Carolina. One infected blue jay was found in Raleigh on Brooks Avenue (not far from the North Carolina State University campus). These recent finds were from birds that were collected earlier this month. We have also had one confirmed human case of Eastern Equine Encephalitis in Pamlico County. It is quite likely we will have additional West Nile Virus-infected birds reported over the next few weeks.
We are likely to see sharp increases in Asian tiger mosquitoes in the coming weeks as a result of recent rainfall. While the rainfall was not enough to put a dent in our drought, it was more than adequate to provide breeding grounds for the mosquitoes. In addition, because of water restrictions, residents are collecting rainwater to water plants. Backyard inspections conducted this week found 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 observed 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.
As we have mentioned repeatedly, it is extremely important to remind people that virtually any standing water source is a potential mosquito breeding ground and needs to be removed wherever possible. Ordinary window screening placed over water collecting buckets and barrels will help exclude mosquitoes. Many of the large barrels being sold in the counties for collecting rainwater are equipped with such screening.
Another approach is to eliminate mosquitoes in such breeding sites is to use the Mosquito Dunks, the doughnut-like tablets that contain Bti (Bacillus thuringiensis israelensis) that 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 a drinking bowls for pets.
Many people are asking about what they can spray for mosquitoes. There are electric and gasoline-powered fogging machines available in retail stores, but as with any do-it-yourself pest control, results may be far less than expected. Fogging your yard does help reduce the number of adult mosquitoes, but it has little (if any) impact on the source of the infestation, i.e., the breeding areas, particularly in many of our residential areas where Asian tiger mosquitoes are very prevalent. We cannot emphasize enough the need for caution and care if someone attempts to use such machines. Users need to wear appropriate safety equipment (such as long-sleeved shirts and pants, goggles, and a respirator) 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 do not understand the concept of property lines and they're just as inclined to fly anywhere (including from untreated areas) in search of a good meal (i.e., you). Mosquito control, chemical or non-chemical, has to be a community effort.
There is likely to be another surge in interest about using the mosquito trapping devices found in the retail stores or sold over the Internet. As we have stated previously, the devices will attract many (but not all) species of mosquitoes. There is a lack of scientifically based data to show that these devices will actually have any impact in reducing mosquito populations and, more far more importantly, provide the type of protection that the public expects. If people want to spend the money for these devices and it gives them some questionable sense of comfort, that's their decision. We still do not recommend these devices as a primary means of preventing mosquito bites or the potential of mosquito-borne diseases. We still advise the careful use of insect repellents, limiting their use on small children.
Information about mosquitoes, West Nile virus and other mosquito borne diseases, with links to important information from the North Carolina Department of Environment and Natural Resources Public Health Management Section can be found on our web site at: http://insects.ncsu.edu/westnile.htm. Information about insect repellents can be found at the following web site: http://insects.ncsu.edu/Urban/repel.htm.
Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Last modified on August 26, 2002 by Stephen J. Toth, Jr.