Most mosquitoes are nuisance pests that cause discomfort or itching. But large mosquito populations can have social, cultural, and economic impacts by limiting outdoor activities such as hiking and other recreation that support local economies.
EPA and CDC continue to emphasize habitat management and controlling immature mosquitoes before they become adults. However, both agencies also recognize the need for space sprays when source reduction and larval control are not feasible.
Pollination
Flies and mosquitoes control one of the world’s most important insect pollinators, enabling many fruit trees and crops to produce their seeds. They also contribute to the formation of natural landscapes and ecosystems by transporting nutrients, soil erosion control, water filtration, buffering floods and storm surges, and providing habitat for aquatic and terrestrial organisms.
Mosquitoes are found throughout the world and can transmit a variety of pathogens to humans, including mosquito-borne viral encephalitis, dengue fever, yellow fever, malaria, and filariasis. Changing environmental conditions, global travel, migration and trade are extending the ecological niches of these mosquitoes and the pathogens they carry, reaching previously uninfected populations with devastating results.
Wetlands are the planet’s most productive habitats, regulating water flow and temperature, providing water and food for wildlife, blunting the impacts of floods and droughts, reducing erosion, and supporting biodiversity. Increasingly, these valuable natural areas are being drained, polluted and lost due to human activities.
A slew of methods are used to control mosquitoes, but the best approach is to reduce mosquito larval habitat through source reduction and increasing natural predators. Larviciding is a good way to do this, but it must be done in such a manner as to not negatively impact the health of natural ecosystems. Only those sites where standing water can’t be eliminated should be larvicided, and the safest products are methoprene and Bti products.
Biodiversity
While mosquitoes get a bad rap for their incessant whining and itchy bites, the insects actually serve a number of vital functions in healthy ecosystems. Mosquitoes produce food for themselves and other creatures, including fish as larvae and birds, bats and frogs as adult flies; they act as pollinators; and their waste products help to fertilize plants.
While some species of mosquitoes, such as Anopheles and Culex, can transmit diseases to humans, most do not. Flies, on the other hand, can carry a number of serious diseases and are found worldwide. Flies are scavengers that feed on nectar and pollen, playing an important role in plant pollination similar to that of bees and butterflies. They also eat decaying organic matter, garbage, sewage and other contaminated substances. Their ability to regurgitate digestive enzymes and pre-digest food externally makes them flexible feeders that can adapt to different ecological niches.
Mosquitoes breed in a variety of habitats, from flooded areas such as marshes and wet meadows to trees, stumps, logs and manmade containers. Biological diversity in wetlands helps to keep mosquito numbers low, and studies have shown that biodiversity in natural landscapes is correlated with the presence of less mosquito-borne disease.
However, alterations of wetlands through drainage, water impoundment and conversion to agriculture, along with the use of chemical pesticides, have disrupted ecosystems. These changes allow mosquitoes to more easily access human habitats, causing them to increase in numbers and become more susceptible to disease transmission.
Food Sources
Flies eat many of the same foods as humans: meat and dairy, poultry, fruits and vegetables. But they also eat garbage and animal waste, including manure, compost, pet dung, soiled litter and composted human food. As a result, they contribute to pollution in lakes, rivers and streams.
In addition, flies are important vectors for disease transmission to humans. They carry and transmit a wide range of pathogens, including the flaviviruses dengue, Zika and yellow fever; protozoan parasites that cause malaria; and a parasitic roundworm (Dirofilaria immitis) responsible for dog heartworm. These diseases can affect four billion people globally. The warmer global climate is expanding the ecological niches of mosquito species that carry these diseases to more extreme latitudes and longitudes, and they are spreading rapidly.
Pestemite provides Mosquito control relies on a number of techniques. Some rely on larviciding the breeding habitats of specific mosquito species, usually by applying a solution to the breeding substrate. The larviciding agent is either a chemical or biological substance that causes the breeding site to be unfavourably suited for the species.
Other strategies target specific biological parameters in the mosquito that determine its ability to transmit pathogens. For example, multiple research groups have developed genetic constructs that target the mosquito immune system to reduce its capability for apathogen transmission. These methods have substantial technical limitations, however. Assembling a mosquito with an anti-pathogenic transgene requires substantial engineering, and tests of this approach to date have shown that immunological interference interferes with insect behaviour and mating in unexpected ways.
Disease Transmission
Mosquitoes are responsible for spreading diseases that can impact human health. The most common mosquitoes are in the Aedes species, which are found worldwide and can transmit dengue fever, chikungunya, yellow fever and Zika virus, along with malaria parasites that affect humans and other animals. These mosquitoes lay their eggs in masses or rafts on the water’s surface, and the black eggs can desiccate and last for months, allowing Aedes to establish itself in new environments.
Female mosquitoes consume blood to develop enough eggs for reproduction. The number of eggs produced depends on the mosquito’s competence, defined as its ability to support pathogen development and spread (Box). This parameter is influenced by complex interactions with the local ecological environment, including insect-pathogen relationships and vector population density.
Researchers have been able to improve the effectiveness of chemical control by understanding mosquito physiology. Studies have shown that the sterilizing compounds PPF and 20E shorten mosquito lifespans without affecting their ability to reproduce, and they inhibit the transmission of malaria parasites.
Communities can reduce their risk of mosquito-borne disease by eliminating potential breeding habitats. This includes keeping grass and brush trimmed away so it doesn’t pile up, making sure that pool covers and table umbrellas don’t hold water, and positioning outdoor objects to minimize contact with the ground or water. In addition, people should wear long sleeves and pants when possible, avoid being outdoors at dusk or after dark, and use mosquito repellent.
