We use adulticide sprays to control adult mosquito populations. Larviciding is not 100% effective. Our county has so many potential breeding sites and after a heavy rain we are unable to treat every ditch and hole in our very large county. Spraying gives us another opportunity to treat mosquito populations. We spray adulticides by trucks with mounted spray units and by airplane. Our airplane allows us to access open spaces with little to no road access. Our spray units are calibrated to maintain an accurate droplet size of each adulticide. This allows us to control and monitor how much pesticide is put out. Like all pesticides our adulticides are regulated by the EPA and are dispersed by our certified pesticide applicators.
Within Galveston County we are currently using two products for adult mosquito control, malathion and permethrin. Switching adulticides reduces the risk of mosquito resistance. Permethrin is usually used within the colder months.
Malathion is an organophosphate that inhibits cholinesterase in mosquitoes. This disrupts their nervous system and leads to paralysis and death in mosquitoes. It’s fast and effective in controlling adult mosquito populations but also low in toxicity for humans and domestic animals. Malathion requires bio-transformation to the phosphate form, this is only carried out by insects.
Permethrin in a synthesized pyrethroid. It emulates naturally occurring insecticides called pyrethrins. Pyrethrins are derived from the extract of chrysanthemum flowers. It's diluted with water and is a fast and effective control against adult mosquitoes. Permethrin has low toxicity in humans and domestic animals.