International Member of National Pest Management Association, USA
MOSQUITOES

Mosquitoes

  • Adult mosquitoes are small, fragile insects with slender bodies; one pair of narrow; and three pairs of long, slender legs
  • They have an elongate "beak" or piercing proboscis
  • The mosquito goes through four separate and distinct stages of its life cycle: Egg, Larva, pupa, and adult
  • There are three common groups of mosquitoes: Aedes, Anopheles and Culex

AEDES MOSQUITOES

  • Aedes mosquitoes have typical black and white stripe markings on their body and legs
  • Eggs of these mosquitoes are laid singly or in rafts and although they may stick to the surface, they may sink if the water is disturbed
  • Aedes prefers clean water for the development of the larvae
  • Only the female aedes mosquito bites as it needs the protein in blood to develop its eggs.
  • Peak biting is at dawn and dusk.
  • The average lifespan of an Aedes mosquito is 2 weeks
  • The mosquito can lay eggs about 3 times in its lifetime, and about 100 eggs are produced each time.
  • The eggs can lie dormant in dry conditions for up to about 9 months, after which they can hatch if exposed to favourable conditions, i.e. water and food
  • Responsible for transmitting dengue fever, encephalitis, and yellow fever

ANOPHELES MOSQUITOES

  • Anopheles mosquitoes go through four stages in their life cycle: egg, larva, pupa, and adult
  • Eggs are laid singly directly on water and are unique in having floats on either side
  • Eggs are not resistant to drying and hatch within 2-3 days
  • Anopheles mosquitoes can be distinguished from other mosquitoes by the palps, which are as long as the proboscis, and by the presence of discrete blocks of black and white scales on the wings
  • Typical resting position: males and females rest with their abdomens sticking up in the air
  • Anopheles mosquitoes are crepuscular (active at dusk or dawn) or nocturnal (active at night)
  • Primary vector of malaria disease

CULEX MOSQUITOES

  • Culex are medium-sized mosquitoes that are brown with whitish markings on the abdomen
  • Typically bite at dusk and after dark
  • Culex lay rafts of eggs on still water in a variety of natural and man-made containers, including tree holes, ditches, sewage and septic system water, storm drains, non-chlorinated swimming and wading pools, decorative ponds, bird baths, flower pots, buckets, clogged gutters, abandoned tires, and water-retaining junk
  • Vectors of important diseases, such as West Nile virus, filariasis, Japanese encephalitis and avian malaria

MOSQUITOES MANAGEMENT

LARVICIDING

  • Larviciding typically involves applying pesticides containing methoprene or Bacillus thuringiensis israelensis or B. sphaericus bacteria, to water where mosquito larvae develop.
  • As mosquito larvae feed, the Bacillus are ingested. Once ingested, a bacterial toxin perforates the mosquito’s gut, killing it.
  • Larvicides containing the insect growth regulator, methoprene, work by disrupting the larva’s metamorphosis, preventing it from developing into an adult.
  • The toxicity of both types of larvicide is quite low, and both are considered safe to use in waters containing fish.

ADULTICIDING

  • Adulticiding is the process of applying a fog of insecticide to reduce the number of adult mosquitoes.
  • Mosquito adulticiding is conducted in the late afternoon hours, as this is the time of high mosquito activity.
  • This type of treatment is only effective if there are adult mosquitoes flying at the time of fogging and if weather conditions are favorable for keeping the fog close to the ground.
  • It does not provide residual protection against future mosquitoes
  • For this reason, adulticiding is done in conjunction with larviciding as treatment processes for mosquito control.