With spring comes mosquitoes. In addition to being a nuisance and causing severe reactions to bites in some people, mosquitoes can also transmit diseases including malaria and St. Louis encephalitis in humans, equine encephalomyelitis in horses, heartworm disease in dogs and cats, and West Nile virus in many species.
What are mosquitoes?
Mosquitoes are insects, thus related to lice, fleas, and flies. Mosquitoes have six legs, a pair of wings, compound eyes, large antennae, and that problematic proboscis with which the females suck blood. (Male mosquitoes eat nectar.)
To make them even more pesky, it is no help that some female mosquitoes can hibernate during the winter and lay their eggs in spring. They generally travel for about 2 miles from their breeding grounds, or even further if blown by the wind.
What is the life cycle of the mosquito?
All mosquitoes need water as a place where they can lay their eggs one at a time, or in "rafts" of up to 200 eggs, depending upon the species. The eggs hatch into larvae about 2 days after being laid. The larvae (also called 'wigglers') live in the water for 7-10 days while maturing into the pupal (also called 'tumbler') stage. In 2-3 days, these pupae have developed into adults and fly away and mate. (If you are wondering how a male and female mosquito find each other, the female's buzzing which is made by her wings is a higher pitch than that of the male.)
Adding up the days necessary for each stage of development, you can see it only takes about 2 weeks (less if it is really warm) for the life cycle to be completed. Add the fact that each female can lay 100-400 eggs, and you can see why you can have so many mosquitoes in a very short time.
How can mosquitoes be controlled?
We can try to eliminate or reduce mosquitoes in several ways, and combining methods is best. We need to:
Eliminate Breeding Sites
One of the most important things to remember is that mosquitoes need stagnant water to reproduce. No water, no reproduction. Control then, is based on removing standing water, which can serve as a breeding site. Think of the things that can hold water:
Reduce Exposure to Adult mosquitoes
Repellents are chemical substances that mosquitoes will avoid. Repellents are useful to people working or playing in mosquito-infested areas, as a way to reduce the risk of being bitten. Repellents are formulated and sold as aerosols, creams, solids (sticks), and liquids. Be sure to read the label carefully and use the product according to the manufacturer's recommendations. Some are for use in the environment, others for clothing, and still others can be used on the skin.
Oil of citronella repellents for the environment: Products containing oil of citronella are used to repel mosquitoes in the space around you. The active ingredient is found in candles, torches, or coils. When burned, they produce a smoke that repels mosquitoes. These should only be used outdoors in ventilated areas. They are only effective when used under windless conditions. Although helpful, they are not as effective as DEET (N,N-diethyl-meta-toluamide) or permethrin-type repellents.
Permethrin-containing repellents for clothing: Repellents containing permethrin are recommended for use on articles such as clothing, shoes, bednets, and camping gear. Permethrin repels and kills mosquitoes as well as ticks and other arthropods. Do NOT use permethrin products on human skin.
Repellents for pets: Permethrins and pyrethrins formulated for pets can be used as repellents to protect your dog. Pyrethrin is a safe repellent for cats and ferrets. Permethrins are NOT safe for cats. Another reason to protect your cat from mosquitoes is that some cats have a mosquito bite hypersensitivity. Since no repellent is 100% effective, heartworm preventatives are still necessary even if a mosquito repellent is used.
DEET-type repellents for human skin: Repellents with ingredients such as diethyl phthalate; diethyl carbate; N, N-Diethyl-3-Methylbenzamide (DEET); and ethyl hexanediol are effective products to use on the skin. There are newer products available which contain microencapsulated repellent, which is less likely to harm plastics and synthetic fibers. There are some other products, such as Avon's Skin-So-Soft® and herbal remedies which are reported to repel mosquitoes, however, their efficacy has not been proven through scientific studies.