Mosquito RepellentsDEET (N,N-Diethyl-m-toluamide) has proven track-record of effectiveness and safety. Highestconcentrations commercially available are not necessary, however; 15-30% DEET is sufficient.Alternatives largely unproven (citronella, oil of lemon eucalyptus, Avon Skin-so-soft…) and notrecommended for small children.Wearing long sleeves and long pants, and avoiding being outside during crepuscular periods(evening, morning) reduces exposure to mosquitoes.*Mosquito control approachesTargeting larvae:Main advantage: larvae found in specific locationsBut habitats can be difficult to find (tree holes) or environmentally sensitive (wetlands)And efforts may disrupt natural controlTargeting adults:widespread so cannot target control effortspesticides need to be applied in areas with people, birds, beesMain advantage: control applied after natural control has taken its toll (no need to kill amosquito that is already dead!)Mosquito control methodsSource reduction (eliminate breeding sites; see cartoon below)Chemical larvicidesAdult sprayingEnvironmentally benign materials (Bti, juvenile hormone mimics), safe for other insects andanimalsBiological/natural control (mosquitoes have their own diseases, mosquitofish, predaceousinsects; FYI mosquitoes are too small for birds/bats to bother with, but mosquitoes will feed onthem!)Emerging genetic control approachesSterilizing insects (non-viable progeny produced)Pathogen incompatiblities (Wolfbachia bacterial insertion prevents dengue virus transmission)Problem: public skepticism of GMOs*Tree hole/container breeding mosquitoesIntraspecific competition forfood among larvae may be intense.95% natural mortality from starvation.A control measure (pesticide, biocontrol organism) may kill many larvae, but competition is thenreduced (fewer starve).With control, just as many or more mosquito adults may be produced, and ones produced may bemore robust (and better vectors).“Control” might make things worse!*Aedes albopictus (Asian Tiger mosquito)Introduced into USA in 1984 in a shipment of old tiresfrom Japan (eggs in tires); spread through southeastern US,up Mississippi valley (now most abundant species in Athens).Major virus vector in SE Asia (e.g. Dengue) so a concern hereAedes japonicus: Most recent invader in GeorgiaMosquito Arbo-Virus Transmission*Arbo-virus transmission (similar for all viral diseases)Mosquito female picks up virus from reservoir (humans, birds) while blood feedingVirus enters gut, penetrates the gut wall into the hemocoel, then migrates to the salivary glands,where it multiples (7-10 days)New host is infected when saliva it injected into bite site when a new blood meal is sought(biological transmission because virus