With environmentalists constantly searching for a safer insecticide to deal with those pesky mosquitoes, naled has often been the choice for many. Having been registered for use since 1959 in the United States, about one million pounds of the organophosphate pesticide have been used every year with seventy percent used towards mosquito control. Primarily produced by AMVAC, naled appears to be an “off-white to straw yellow liquid with a sharp, pungent odour.” While reasons for success are relatively simple, its impact upon the environment and society are not.
Farmers and gardeners alike face the common threat of mosquitoes and the common problem of using a safe yet effective pesticide to deal with them. Accordingly, naled attacks adult mosquitoes hence its classification as an adulticide. Applied by trucks or planes, the aerosol droplets of naled stay suspended in the air temporarily and kill adult mosquitoes upon contact. Like all organophosphate insecticides, naled works by inhibiting acetylcholinesterase (AChE) which is an important enzyme that is involved in the transmission of nerve impulses through nervous tissue. Without this enzyme, the transmissions between nerves become jammed which ultimately leads to paralysis and death.
Because naled effects AChE and is thus toxic to the nervous system, it has been shown to cause some negative side effects in humans such as headaches, nausea and diarrhea. In addition, naled also affects insects that are helpful to the environment and the farmers that use it. Insects such as honey bees are highly susceptible to naled’s effects and the alfalfa leaf cutting bees and alkali bees are at an even greater risk. Parasitoid wasps that lay their eggs in other juvenile insects are also at risk from this pesticide. Essentially, naled limits the diversity of the insect population in the area that it is sprayed. Insects are not all that naled effects, however. Fish such as lake trout, rainbow trout, cutthroat trout and catfish find naled to be highly toxic. For human kind’s feathered friends, the birds, naled can be moderately to highly toxic with the most sensitive bird being the Canada goose. Naled has also been proven to effect reproduction in Mallard ducks. After exposed to the insecticide, these ducks laid fewer eggs and consequently hatched fewer ducklings than unexposed ducks. And just when it seemed the plants were safe, naled has also been known to cause brown lesions in celery and bronzing in strawberries. As well, tomato pollen germination was also greatly reduced.
While naled is not popularly used internationally, it is registered for use in some of the major developed countries of the world such as Canada, the United States, India and Australia. In Canada, the Pest Management Regulatory Agency (PMRA) represents a branch of Health Canada in charge of pest control products and minimizing the risks associated with the use of these products. Most recently, in regards to naled, the PMRA was informed by United Agri Products, a registrant of the only commercially produced insecticide containing naled, that its product label will be amended. The label will be amended to prohibit the use of the product Clean Crop Dibrom Insecticide from being used around residential areas including homes, parks, lawns, schools and playing fields. While naled products have not been banned, they have become prohibited for use in certain areas as outlined by the case with United Agri Products. The PMRA also claimed that the United States was also in the process of reassessing naled use. While both Canada and the U.S. use naled for similar purposes, U.S. registrants have expressed an interest in the cancellation of certain naled products such as naled-impregnated pet collars. Legislation for naled has proven to be more reliant on the individual user’s voluntary actions. Companies like United Agri Products chose to put the amended labeling on their products; it was not ordered upon them.
Risks and Benefits
Naled is a popular organophosphate insecticide used to control mosquito population. Various municipal governments have decided to use naled as a response to the arrival of West Nile Virus. This method of mosquito control could significantly reduce the threat of West Nile Virus by decreasing the adult mosquito population. Naled is also used as a fumigant to control other agricultural pests in green houses. Furthermore, naled is used by veterinarians to kill parasitic worms in dogs.
Naled like other organophosphates, can over-stimulate the nervous system causing nausea, dizziness, or confusion. In cases of severe exposure, it can cause convulsions, respiratory paralysis, or even death. It has been studied that excessive exposure to naled can cause increased aggressiveness and a deterioration of memory and learning. Although the molecule itself may not be a severe risk to human health, naled breaks down into a more toxic organophosphate insecticide called dichlorvos. This molecule is known to interfere with parental brain development. They also cause cancer (specifically leukemia and pancreatic cancer), according to the International Agency for Research on Carcinogens.
Bronson, Charles. (N/A). Frequently Asked Questions about Naled. Retrieved March 22, 2006, from Florida Department of Agriculture and Consumer Services.
Cox, Caroline. (2002). Insecticide Fact Sheet: Naled (Dibrom). Retrieved March 20, 2006, from Journal of Pesticide Reform.
Web site: http://www.pesticide.org/naled.pdf
Health Canada. (2003). Update on the Re-evaluation of Naled in Canada. Retrieved March 20, 2006, from Pest Control Canada.
Myers, Tom. (2002). Naled for Mosquito Control. Retrieved March 22, 2006, from U.S. Environmental Protection Agency.
Hornsby, A.G., Wauchope, R. Don, Herner, A. (1995). Pesticide Properties in the Environment. New York: Springer.