wide-scale use of ddt for mosquito control. control of adult mosquitoes is the most familiar aspect of mosquito control to most of the public. it is accomplished by ground-based applications or via aerial application of residual chemical insecticides such as duet. generally modern mosquito-control programs in developed countries use low-volume applications of insecticides, although some programs may still use thermal fogging. beside fogging there are some other insect repellents for indoors and outdoors. an example of a synthetic insect repellent is deet. a naturally occurring repellent is citronella. indoor residual spraying (irs) is another method of adulticide. walls of properties are sprayed with an insecticide, the mosquitoes die when they land on the surface covered in insecticide. anti-mosquito fogging operation p.ramachandrapuram village in india to control adult mosquitoes in india, van mounted fogging machines and hand fogging machines are used. use of ddt main article: ddt ddt was formerly used throughout the world for large area mosquito control, but it is now banned in most developed countries. walls on irs-treated bathroom on the shores of lake victoria. the mosquitoes remain on the wall until they fall down dead on the floor. controversially, ddt remains in common use in many developing countries (14 countries were reported to be using it in 2009), which claim that the public-health cost of switching to other control methods would exceed the harm caused by using ddt. it is sometimes approved for use only in specific, limited circumstances where it is most effective, such as application to walls. the role of ddt in combating mosquitoes has been the subject of considerable controversy. although ddt has been proven to affect biodiversity and cause eggshell thinning in birds such as the bald eagle, some say that ddt is the most effective weapon in combating mosquitoes, and hence malaria. while some of this disagreement is based on differences in the extent to which disease control is valued as opposed to the value of biodiversity, there is also genuine disagreement amongst experts about the costs and benefits of using ddt. notwithstanding, ddt-resistant mosquitoes have started to increase in numbers, especially in tropics due to mutations, reducing the effectiveness of this chemical; these mutations can rapidly spread over vast areas if pesticides are applied indiscriminately (chevillon et al. 1999). in areas where ddt resistance is encountered, malathion, propoxur or lindane is used. toxicantdosage in g/m2average duration of effectiveness in months ddt1 to 26 to 12 lindane0.53 malathion23 propoxur23 mosquito traps a light trap that attracts and captures mosquitoes. a traditional approach to controlling mosquito populations is the use of ovitraps or lethal ovitraps, which provide artificial breeding spots for mosquitoes to lay their eggs. while ovitraps only trap eggs, lethal ovitraps usually contain a chemical inside the trap that is used to kill the adult mosquito and/or the larvae in the trap. studies have shown that with enough of these lethal ovitraps, aedes mosquito populations can be controlled. a recent approach is the automatic lethal ovitrap, which works like a traditional ovitrap but automates all steps needed to provide the breeding spots and to destroy the developing larvae. in 2016 researchers from laurentian university released a design for a low cost trap called an ovillanta which consists of attractant-laced water in a section of discarded rubber tire. at regular intervals the water is run through a filter to remove any deposited eggs and larva. the water, which then contains an 'oviposition' pheromone deposited during egg-laying, is reused to attract more mosquitoes. two studies have shown that this type of trap can attract about seven times as many mosquito eggs as a conventional ovitrap. some newer mosquito traps or known mosquito attractants emit a plume of carbon dioxide together with other mosquito attractants such as sugary scents, lactic acid, octenol, warmth, water vapor and sounds. by mimicking a mammal's scent and outputs, the trap draws female mosquitoes toward it, where they are typically sucked into a net or holder by an electric fan where they are collected. according to the american mosquito control association, the trap will kill some mosquitoes, but their effectiveness in any particular case will depend on a number of factors such as the size and species of the mosquito population and the type and location of the breeding habitat. they are useful in specimen collection studies to determine the types of mosquitoes prevalent in an area but are typically far too inefficient to be useful in reducing mosquito populations. factor eof1 research is being conducted that indicates that dismantling a protein associated with eggshell organization, factor eof1 (factor 1), which may be unique to mosquitoes, may be a means to hamper their reproduction effectively in the wild without creating a resistant population or affecting other animals. proposals to eradicate mosquitoes some biologists have proposed the deliberate extinction of certain mosquito species. biologist olivia judson has advocated "specicide" of thirty mosquito species by introducing a genetic element which can insert itself into another crucial gene, to create recessive "knockout genes". she says that the anopheles mosquitoes (which spread malaria) and aedes mosquitoes (which spread dengue fever, yellow fever, elephantiasis, zika, and other diseases) represent only 30 out of some 3,500 mosquito species; eradicating these would save at least one million human lives per year, at a cost of reducing the genetic diversity of the family culicidae by 1%. she further argues that since species become extinct "all the time" the disappearance of a few more will not destroy the ecosystem: "we're not left with a wasteland every time a species vanishes. removing one species sometimes causes shifts in the populations of other species — but different need not mean worse." in addition, anti-malarial and mosquito control programs offer little realistic hope to the 300 million people in developing nations who will be infected with acute illnesses each year. although trials are ongoing, she writes that if they fail: "we should consider the ultimate swatting." biologist e. o. wilson has advocated the extinction of several species of mosquito, including malaria vector anopheles gambiae. wilson stated, "i'm talking about a very small number of species that have co-evolved with us and are preying on humans, so it would certainly be acceptable to remove them. i believe it's just common sense." insect ecologist steven juliano has argued that "it's difficult to see what the downside would be to removal, except for collateral damage". entomologist joe conlon stated that "if we eradicated them tomorrow, the ecosystems where they are active will hiccup and then get on with life. something better or worse would take over." however, david quammen has pointed out that mosquitoes protect forests from human exploitation and may act as competitors for other insects. in terms of malaria control, if populations of mosquitoes were temporarily reduced to zero in a region, then this would exterminate malaria, and the mosquito population could then be allowed to rebound.