Mosquito spraying is done using mounted fogging units to apply insecticides as an ultra-low-volume (ULV) spray. These units spray units dispense very fine aerosol droplets (fog) that stay aloft and kill mosquitoes on contact. The amount of insecticide used in mosquito spraying is small compared to the area treated, usually about 3 to 5 ounces per acre, which minimizes exposure and risks to people and the environment. Mosquito spraying is also done by thermal foggers that use an oil carrier that is heated to disperse the pesticide in a dense smoke-like fog.
During mosquito spraying , flying mosquitoes within the treated area are killed. Although the local mosquito population is reduced for a few days, fogging does not prevent mosquitoes from re-entering the area.
The most commonly used products in mosquito spraying are pyrethrins, synthetic pyrethroid insecticides (such as Scourge ® and Anvil ®)and malathion. Pyrethrins are insecticides derived from the extract of chrysanthemum flowers. Pyrethroids are human made forms of pyrethrins. Both of them act as contact poisons, affecting the insect’s nervous system. For mosquito spraying they are combined with a synergist (such as piperonyl butoxide) that allows the insecticide to be more effective by restricting the enzyme that insects use to detoxify the pyrethrins.
Pyrethrins and pyrethroids are use in mosquito spraying without posing unreasonable risks to human health when applied according to the label although, in high dosage, pyrethroids can affect the nervous system, coughing, wheezing, shortness of breath, chest pain, runny or stuffy nose. Regarding the wild life and the environment these two insecticides do not pose unreasonable risks, also. When used in mosquito spraying they are low in toxicity to mammals, and are practically nontoxic to birds. However they are toxic to fish and to bees. Therefore E.P.A (Environmental Protection Agency) prohibits the mosquito spraying to open water or within 100 feet of lakes, streams, rivers or bays.
Malathion is an organophosphate insecticide that has been registered for the first time in the United States in1956. It is used to kill insects on agricultural crops, on stored products, on golf courses, in home gardens, and in outdoor sites where trees and shrubs are grown at home and also used in mosquito spraying. Malathion comes in two forms: a pure form of a colorless liquid and a technical-grade solution (brownish-yellow liquid), which contains malathion (greater than 90%) and impurities in a solvent. The technical-grade malathion smells like garlic.
For mosquito spraying, this substance is applied at a maximum rate of 0.23 pounds (or about 2.5 fluid ounces) of active ingredient per acre, so it doesn’t pose unreasonable risk to human health. However, at high doses, malathion, like other organophosphates, can overstimulate the nervous system causing nausea, dizziness, or confusion. Severe high-dose poisoning with any organophosphate can cause convulsions, respiratory paralysis, and death. Malathion degrades rapidly in the environment, especially in moist soil, and it displays low toxicity to birds and mammals, but is highly toxic to beneficial insect (ex honey bees) too. Therefore E.P.A set a few regulations for the use of this product.
So these would be the most important aspects of mosquito spraying that you should be concerned about along with the main chemical components used in this process.
