Mosquitoes are a common nuisance around
standing water. Unfortunately, they can also be disease vectors. Mosquito
control in ponds is essential for maintaining an enjoyable and safe
environment.
Mosquitoes are small, gnat-like flies. The larval stages are aquatic, and
mosquito larvae feed on algae and bacteria at the surface of standing water.
Some species are adapted to live in salt marshes, while others live in swampy
areas or ponds. Many species can even thrive in artificial reservoirs of water.
Discarded containers and old tires are common habitats for mosquito larvae.
When mosquitoes mature into adults, they take to the air and become pests. Male
mosquitoes feed exclusively on nectar and plant juices, and most females feed
on the same substances. Although the females can survive on plant juices, they
require animal blood to produce eggs. The blood is broken down into amino acids
that are used to create the yolk of mosquito eggs. Without a meal of blood, the
female mosquitoes lack these amino acids and eggs will not develop.
Mosquito saliva contains proteins to prevent blood from immediately clotting as
the insects feed. The itching felt after a mosquito bite is an allergic
reaction to the proteins in the mosquito’s saliva. Some species of mosquitoes
also carry disease-causing viruses and parasites. These harmful organisms can
be transmitted to animal hosts during the feeding process. Yellow fever, dengue
fever, West Nile virus and malaria are common examples.
Although they live in the water, mosquito larvae must come to the surface to
breathe. They have tiny openings in their bodies known as spiracles, and air
enters through these opening. Most pond mosquito measures take advantage of this
requirement by increasing the surface tension of the water to prevent the
spiracles from reaching air, or by concentrating toxins at the surface.
The bacillus thuringiensis israelensis is harmless to other aquatic life but is
quite toxic to mosquito larvae. Products containing this bacteria, which is
often abbreviated BTI, are floated on pond surfaces. They release the BTI,
which attacks and kills mosquito larvae, over an extended period of time. The
products are often called mosquito dunks, donuts, pellets. It also comes in a
liquid biological mosquito control.
Barley straw and barley straw extracts can also be used as mosquito control in
ponds. These materials reduce algae growth and starve mosquito larvae. Some
products also incorporate BTI into barley straw. These materials have the added
benefit of clarifying pond water.
The addition of small freshwater fish, called mosquito fish, is another common
means to keep mosquitos to the minimum. These fish occur in two species, the
eastern mosquito fish and the western mosquito fish, and are native species in
the US. They are voracious feeders, and small populations are usually
sufficient to keep mosquitoes under control. In ponds that are too limited to
support mosquito fish, BTI-containing products are usually the best control
measures.
