DDT Repeat fromNov 08 Mosquito control measures may be divided into 3 steps: I. Anti-larval measures Anti-adult measures Protection against mosquito bites Anti-larval measures a. Environmental control (Source reduction) Source reduction means elimination of the breeding places of mosquitoes. This is the most impoant step in controlling mosquitoes. Source reduction methods include: - Minor engineering methods such as filling, leveling and drainage of breeding places - Water management (such as intermittent irrigation) - Changing the salinity of water (this makes water unsuitable for mosquito breeding) b. Chemical control Chemical control methods are: i) Mineral oil- oil spreads on water forming a thin film, which cut off the air supply to the mosquito larvae and pupae ii) Paris Green- It is a stomach poison (that is it must be ingested in order to work). It mainly kills the Anopheles larvae because they are surface feeders. Bottom feeding larvae are also killed when Paris green is applied as a special granular formulation. iii) Synthetic insecticides? The common synthetic larvicides used are: Abate, Malathion, Fenthion, and Chloropyrifos The organochlorine compounds e.g. DDT, HCH are not used for larviciding operations because of their long residual effect, water contamination and increased risk of developing resistance in the vector mosquitoes. c. Biological control- it includes larva eating fishes such as Gambusia affinis and Lebister reticulates. Anti-adult measures a.Residual sprays- e.g. DDT. Lindane, Malathion, OMS-33. DDT is the insecticide of choice. b.Space sprays- Space sprays are those that are sprayed into the atmosphere in the form of a mist or fog to kill mosquitoes. e.g. Pyrethrum, Malathion, Fenitrothion c. Genetic control These include sterile male technique, cytoplasmic incompatibility, chromosomal translocations, sex distoion, and gene replacement. These methods are still in research phase. Protection against mosquito bites a.Mosquito net b.Screening- screening of buildings with copper or bronze gauze is costly but excellent method. c. Repellants