Master Gardener^sm Column for the Week of August 15, 2005
Charlie Spencer
Brunswick County Extension Master Gardener^sm Volunteer

The recent rains we've experienced will undoubtedly trigger a spike in mosquito activity in the ensuing weeks. Populations of Asian tiger mosquito (ATM) are likely to rise significantly in many areas which means that NOW is the time for residents to take steps to reduce populations by eliminating breeding sites around their property.

Containers that fill with water should be discarded or at least emptied. Bird baths should be flushed out (the birds will appreciate the fresh water too!) And… it's time to get out the ladder and clean out those debris-clogged gutters.

Surveys conducted in areas of our state have found that the dishes under potted plants and the tarps over wood piles, boats, etc. are particularly difficult to eliminate as sources of mosquito production because they often get overlooked. Keep your thirsty plants sated water-wise but don't leave standing water in the dish beneath the pot. Likewise, storm sewers and drainage ditches along roadsides become clogged with silt and vegetation as well as the beverage bottles and other trash that some people seem to pride themselves on being able to toss out and over the top of the car while speeding down the road. Remove debris and/or report drainage problems to the appropriate state or municipal agency.

We've gotten several inquiries about the widely advertised home spray systems for mosquito control. To date, there has been no scientifically-based information (i.e., data that consists of more than a collection of anecdotes from the manufacturer and/or users) available on how effective these misting systems are in reducing mosquito biting activity. Obviously, if people want to spend the money to have such a system installed it's their choice. However, we cannot stress enough the importance of understanding that they are dispersing an insecticide (pyrethrum) into the air around their house and it should NOT be done when people (particularly children and the elderly) are in the vicinity or when food is exposed on tables, grills, etc. Also, on windy days, the mist is likely to drift downwind also limiting its impact on mosquitoes in the vicinity.

There are several brands of mosquito traps out there--these traps do catch mosquitoes; however, we have not seen data that clearly demonstrate if a single trap in a yard will significantly reduce biting incidents which is ultimately what the consumers are looking for when they purchase traps. So, we’re not saying people should or should not buy them. We’re simply offering the proverbial “do so at your own risk.” Many of the traps use a chemical called “octanol” which attracts a wide variety of the mosquito species that are out dusk until dawn along with vampires and werewolves. However, octanol is not effective in attracting the day-flying Asian tiger mosquito (ATM) which is the most common “yard-inhabiting” mosquito species in North Carolina. For the ATMs, you need a chemical called “Lurex.” So, people should read the product label “carefully” and check to see if the trap they’re intending to buy contains both lures. Again, we don’t consider these traps or the misting system to be replacements for residents getting off their collective neighborhood rear ends and eliminating the breeding sites in yards and community areas.

We still stress the need for personal protection. DEET remains the most commonly used repellent although the EPA recently approved some new alternative chemicals. You can read an earlier press release from the CDC concerning these repellents: www.cdc.gov/od/oc/media/pressrel/r050428.htm. Repellents should be used diligently and carefully, particularly on children. They should be applied ONLY to exposed skin and/or clothing. You can read more about mosquito control and repellents on the Extension Entomology Department Web site insects.ncsu.edu/Urban/westnile.htm. You will also find links there to additional information and downloadable brochures at the North Carolina Department of Environment and Natural Resources Web site (NCDENR).

Information for this column was provided by Charles Apperson and Mike Waldvogel, Extension Entomology Specialists at North Carolina State University.

Recommendations for the use of chemicals are included in this article as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina State University, North Carolina A&T State University, or the 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 regulations and examine a current product label before applying any chemical. For assistance, contact the North Carolina Cooperative Extension Service.

Send your gardening questions or comments to: Brunswick County Master Gardener Column, P.O. Box 109, Bolivia, NC 28422, or call (910) 253-2610. Enclose a self-addressed stamped envelope if requesting information or a reply. Answers may be printed in this column.

For further information or assistance, please e-mail:
Charlie Spencer, Brunswick County Extension Master Gardener^smVolunteer

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Date Created 8/11/2005