Mosquitoes on the Rise Following the Rains

If you have been outside at all the last couple of evenings like me, you feel like a pin cushion or feel like you are getting a workout in karate from all the swatting you had to do to keep the mosquitos off of you.  As hard as I tried, I have been unsuccessful judging by the bites I have on my arms.  While visiting with Sonja L. Swiger, PhD, Entomologist Specialist of Texas A&M AgriLife Extension Service located in Stephenville she told me “Mosquitoes affect the health of people and animals more than any other insect pest worldwide.” Biting female mosquitoes transmit many disease-causing organisms, including encephalitis, malaria, and yellow fever.  In addition to their impact on human and animal health, several species of mosquitoes are what is referred to as “nuisance” mosquitoes.  Mosquito populations can occur anywhere in Texas.  To control mosquitoes effectively and economically, you need to understand their life cycle, be able to identify the mosquito species in your area and know the management steps that provide the best control for different species and at specific locations.

            The mosquito life cycle consists of an egg that is laid near or on water, in moist soil or even in locations where the eggs can lay dormant for up to 2 years awaiting rain, typical of many floodwater mosquitoes. An aquatic larva will then hatch from the egg.  The larva will go through four stages, growing in size each time, and will filter feed on organic material in the water. The next life stage is referred to as a pupa, a resting stage where the wingless/legless larva turns into a winged/legged adult. Adult female mosquitoes typically live for about a week to a month, and can take multiple bloodmeals throughout this time period.  Only females bite to obtain blood for making eggs.

            Adult mosquitoes are long-legged flies that have two wings with scales on the veins. Many are fairly small in size but a particular floodwater group called Psorophora is relatively large in size. Mosquitoes are divided into groups based on where the females lay their eggs and where the larvae develop: permanent pools, transient water, floodwater and artificial containers and tree holes.  The control strategies differ for each group.

            The adult mosquitoes around your home may have come from a breeding site near or far away, depending on the species, wind patterns, and the flight habits of the females:

·         Aedes aegypti and Aedes albopictus breed primarily in and around human habitations and fly short distances, usually only about 200 yards.

·         Most Anopheles mosquitoes have a flight range of about 1 mile. Psorophora species have flight ranges of at least 5 miles.

·         Some salt-marsh mosquitoes in the genera Aedes can disperse with the prevailing winds for 20 to 40 miles or more away from the larval development sites.

To manage mosquitoes and protect yourself against bites, always follow the 4 D’s:

·         Dusk and Dawn – avoid being outside when mosquitoes are searching for a bloodmeal, this is at the early morning hours and in evening before the sun goes down.  Although some species are daytime biters most prefer dusk and dawn.

·         Drain – empty any standing water found on you property or store items so that they cannot hold water.  This can include all types of things – buckets, wheelbarrows, kiddie pools, toys, dog bowls, water troughs, etc.

·         Dress – If out during mosquito feeding hours, wear long sleeves and pants in plain colors.  Also avoid attracting them with excessive amounts of perform or aftershave.

·         Defend – any time you go outside for an extended period of time, wear an insect repellant.

Additional means of controlling for mosquitoes includes:

·         Sanitation: Remove mosquito food, water, and shelter.

·         Biological control: Use mosquito fish, nematodes, and Bacillus thuringiensis israeliensis toxin and Bacillus sphaericus.

·         Mechanical control: Maintain window screens and alter building designs.

·         Chemical suppression: Use insecticides against larvae and/or adults.

            Mosquitoes can affect people and animals by feeding on blood annoy people, birds, mammals, and other vertebrates. They disrupt outdoor work and recreational activities. If enough mosquitoes are in an area, they can cause severe blood loss and slow the growth of livestock.  Also mosquitoes affect people and animals by transmitting disease organisms.  The most common of these diseases now in Texas are West Nile Virus and Chikungunya, as well as dog and cat heartworm.

            The rains don’t seem to be going away anytime soon so protect yourself and try to follow these guidelines.  I am not the one who decides when the rain stops, but I do know usually in Texas when it stops it stops.  So for those of you that want it to quit raining remember what the lake looked like a month ago, six months ago and on and on.  For more information please contact the Wise County Extension office at 940-627-3341.