Larval source management (LSM) is the management of mosquito breeding sites and that the objective of LSM is to reduce the number of mosquito larvae and pupae thereby reducing the number of vectors reaching the adult stage. While mosquito nets and IRS remain the backbone of malaria vector control, larval source management is an additional strategy for malaria elimination.

Larval habitat

Anopheline larvae are found in a wide range of habitats (e.g., rice fields, ditches, puddles, the edges of streams and rivers, fresh and brackish marshes, and mangrove swamps) but generally tend to avoid highly polluted water.

An abundance of adult mosquitoes depends on:

  • The number, type and size of potential larval habitats.
  • Their distance from blood meal sources.
  • The density of larvae in the larval habitats.
  • Temperature, rainfall, and soil type.
  • Larval habitats may be stable or dynamic, appearing briefly after rainfall.
Types of LSM
  • Habitat modification: a permanent alteration to the environment (e.g., land reclamation or surface water drainage).
  • Habitat manipulation: a recurrent activity (e.g., water-level manipulation, flushing of streams, the shading or exposure of habitats).
  • Larviciding: the regular application of a biological or chemical insecticide to water bodies.
  • Biological control: the introduction of natural predators into water bodies (e.g., example predatory fish or invertebrates).
 How to map larval habitats and water bodies
  • Freshwater or brackish (slightly salty) water, especially if it is stagnant or slow flowing.
  • Small rain pools, hoof-prints, drains, and ditches with stagnant water in and around the village.
  • Streams, which should be searched at the edges where there is vegetation and where water moves more slowly.
  • Ponds, lakes, swamps, and marshes where larvae usually occur in vegetation around the edges but can sometimes be found far from the shore amongst floating vegetation.
  • Swamps, rice field, and reservoirs.
  • Special sites, such as wells, abandoned swimming pools, and water containers made of cement.
  • Drainages in urban and peri-urban areas and alongside roads.
  • Conducting surveys of larval populations in a systematic manner so that all larval sources may be logged and categorised.
  • These data need to be organised collectively in an accessible format such as a map.
  • If available, a geographic information system (GIS) should be used.
Example of a larval data capturing tool form

It is essential to check all possible sites, even those that are difficult to reach to identify larval habitats.

Potential larval habitats include:

The process to map these sites includes:


Last modified: Monday, 15 June 2020, 10:29 AM