|
GENERAL INFORMATION
The Grand Forks Mosquito Control Program received overwhelming approval during a City of Grand Forks ballot measure in November 7, 1996. The citizens voted 91.8% to continue a mosquito control program implemented as a two year pilot test during 1995 and 1996. The program is designed to promote health and well being by protecting the public from disease and a level of annoyance by mosquitoes in an environmentally sensitive manner.
The mosquito problem in the city of Grand Forks is generated by two species of mosquitoes, the Aedes and Culex. The plan to control these insects must be based on an understanding of their life cycle, reproductive cycle, habitat, and range of travel. A comprehensive mosquito control program employs all phases of mosquito control, such as source reduction, larviciding, adulticiding (ground spraying), and public education.
The Aedes mosquitoes are a floodwater mosquito. These mosquitoes lay their eggs on the ground in areas that are usually covered with water at a later time. The eggs need water to hatch into larvae and to continue their life cycle. The mosquito remains in the larval stage for several days (3 - 10 days on average, depending on temperature and species) before transforming into the pupae stage. The pupae stage is a resting stage for the mosquito before it transforms into an adult. Once the eggs hatch, the cycle from egg to adult takes about seven to fourteen days in the Grand Forks area. The time it takes for the mosquito to complete its life-cycle is dependant on temperature and species. The adult female mosquito mates almost immediately and then seeks a blood meal to nourish the eggs before laying additional eggs. The life cycle then begins again. Mosquito eggs can lie dormant for several years before receiving enough water to hatch. The female mosquito has an effective range of five to ten miles, but can move as far as forty miles to obtain a blood meal.
The Culex mosquito, specifically the Culex tarsalis, has significance not only as a nuisance, but also as a potential carrier of the West Nile virus, St. Louis Encephalitis, and Western Equine Encephalitis, which can be deadly to humans.
The Culex mosquito lays her eggs in standing water, foul or clear. The habitats generally preferred are open, sunny areas, but shaded areas with vegetation are also used. The Culex mosquito is a container-breeding mosquito. That container may be as small as a flower vase or as large as an ornamental pond. The egg to adult life cycle can be completed in seven to 10 days, dependent on the weather. The adult female mosquito may expect to live approximately four to six weeks, during this time seeking many blood meals and laying thousands of eggs. The Culex mosquito can travel up to 25 miles from a breeding site, but generally stays close to its origin because winds in excess of 6 mph inhibit the flight of the Culex mosquito.
The policy for adulticiding (ground spraying program) requires that the entire city be sprayed to reduce the numbers of mosquitoes when the number of mosquitoes trapped per night exceeds an average of 100 per trap. The collection of this information is available through a network of mosquito traps set up at various sites within the city. As a result of the information gathered, a responsible decision can be made as to the timing and justification of a ground spray effort. Without this information and guidelines, inappropriate spraying of pesticide throughout the city might occur. This option contains a measuring device that is essential to any mosquito control program. The results, through a network of traps, can be monitored and recorded.
The program, wherever possible, employs the use of source and site reduction. This activity is directly coordinated under the Soil Conservation Service and the U.S. Department of Fish and Wildlife. The public education program consists of providing to the citizens information regarding the dumping of water from tires, cans, eaves, troughs, etc.
The use of any type of insecticide poses a certain amount of risk to the environment. The insecticides chosen are the most cost effective and environmentally sound to minimize the risk to the environment. The budget also includes funding to evaluate biological control alternative methods on an ongoing basis. It is the intent of the program to reduce the mosquito population without harming the environment. While the Environmental Protection Agency considers the chemicals used in ground spraying safe for use as intended, exposure to direct spraying of humans should be avoided. Chemically sensitive people would need to be well aware of the type of chemical used so their potential risk can be minimized.
The type of products used in the ground spraying operations are synthetic pyrethroids. These products are toxic to adult mosquitoes. There is a risk to the environment when using any pesticide. Proper education, training, and State certification of all staff members minimizes the risk to the environment.
The Grand Forks mosquito control program is funded through a $2.50 per month charge on the water bill to provide funding in the amount of approximately $740,000 annually. |