RESIDENTS CAN HELP CONTROL, PROTECT THEMSELVES FROM MOSQUITOES

DALLAS – Anticipating a significant increase in the state’s mosquito
population, Texas A&M AgriLife Extension Service entomologists are offering
tips on how Texans can help slow mosquito breeding in backyards and protect
from being bitten.

“Mosquito populations are booming throughout the state and will likely
not go away anytime soon after all our rains and flooding,” said Dr. Mike
Merchant, AgriLife Extension urban entomologist in Dallas. “Not all of
the mosquitoes swarming us right now are likely to carry disease, but West
Nile virus-infected mosquitoes are beginning to show up in traps.”
[2]
The Asian tiger mosquito shown here is one of the two mosquito species
known to commonly transmit the chikungunya virus. The other is the closely
related yellow fever mosquito. Both species are  found in Texas. (Texas
A&M AgriLife Extension Service photo by Dr. Mike Merchant)

Texas Department of State Health Services recently announced the first 2015
case of West Nile virus in the state, and Dallas County Health and Human
Services just issued a health advisory reporting its first positive
mosquito pool of the year.

Merchant added that chikungunya, another disease transmitted by mosquitoes,
is on the radar of U.S. and state health officials as a growing concern. He
said the virus is regularly brought into the U.S. by travelers, but as yet
a human-to-mosquito-to-human cycle has not developed in Texas.

“This could change, however, as it did last year in Florida where a
handful of cases occurred among Floridians who had not traveled to the
Caribbean,” Merchant said. “The principal mosquito vectors of
chikungunya include the Asian tiger mosquito, Aedes albopictus, and its
close relative, the yellow fever mosquito, Aedes aegypti. Chikungunya
frequently comes with a very bad headache, joint pain, rash and fever.
 There is no treatment for or vaccine to protect from this disease.”

For more information about where mosquitoes can breed, and how to identify
Aedes and other mosquitoes, Merchant suggested going to AgriLife
Extension’s Mosquito Safari website, http://mosquitosafari.tamu.edu[3].

Humans are not the only ones to suffer from mosquito-borne diseases,
AgriLife Extension experts noted.

“Mosquitoes can also be vectors for dog heartworm,” said Dr. Sonja
Swiger, AgriLife Extension livestock/veterinary entomologist in
Stephenville.

According to Swiger, an infected mosquito can pass tiny heartworm parasites
on to any uninfected dog it bites. Heartworm causes lasting damage to
heart, lungs and arteries, and can affect the dog’s quality and length of
life. In addition, horses are susceptible to several encephalitis diseases,
including West Nile virus, and should be vaccinated every year.

Swiger said that to control mosquitoes effectively and economically,
everyone should understand their basic life cycle and be familiar with the
important mosquito types. According to Swiger, mosquitoes can be divided
into two groups based on where they lay their eggs. For example, floodwater
mosquitoes lay eggs on the ground in low spots, and these eggs hatch when
it rains and the low area fills with water.

“With the unusually high May rainfall, these mosquitoes are common now
and likely to remain so during the duration of the rain,” she said.
“Floodwater mosquitoes are good fliers and can travel many miles from
their breeding sites in temporary pools, roadsides and low lying areas.”

She noted there is little people can do on their own property to protect
themselves from floodwater mosquitoes, other than stay indoors or wear
repellent.

“We have more control over other mosquitoes that breed in containers and
live closer to town,”  Swiger said. “Container breeding mosquitoes
include some of the most significant species that may negatively affect
human health, including the common house mosquito.”

The entomologists referred to what they called “the four D’s” as a
general means for people to help manage mosquitoes and protect against
bites. These are:

— Dusk/Dawn – Avoid being outside when mosquitoes are searching for a
blood meal, which is usually in the early morning hours and just before the
sun goes down. While some species are daytime biters, most prefer to feed
at dusk and dawn.

— Drain – Empty standing water from “containers” around your home
and work areas, such as buckets, wheelbarrows, kiddie pools, toys, dog
bowls, water troughs, tires, bottles, etc. Make improvements that allow
standing water to run off following rains.

— Dress – If out during mosquito feeding hours, wear long sleeves and
pants in plain colors. Avoid attracting them by wearing excessive amounts
of perform or aftershave.

— Defend – Any time you go outside for an extended period of time, wear
an insect repellent.

Dr. Charles Allen, AgriLife Extension entomology program leader in San
Angelo, said mowing tall weeds and grass can help eliminate some mosquito
resting areas.

“When mosquito populations are high, labeled contact insecticides can be
used to knock down adults,” he said. “For greatest effectiveness,
sprays should be directed to shady mosquito resting areas. In addition,
insecticide-based misting systems can be effective short-term, but repeated
applications can cause insecticide resistance or be harmful to non-target
insects and may result in loss of control. These systems are most likely to
be effective if timers are set to spray when mosquitoes are most active.”

Allen said there are also techniques that can help control larval stage of
mosquitoes in water.

“Mosquito dunks containing insect growth regulators or Bti, the mosquito
larva’s bacterial natural enemy, can be used in water that cannot be
dumped or drained to reduce mosquito populations,” he said.

Products that apply a surface film or oil on the water can also be used to
reduce larval mosquito and pupal populations by preventing them from
getting air through their breathing tubes, he said.  The use of films or
oils should be limited to locations without any other organisms, since it
will prevent oxygen to the non-target organisms as well.

According to Merchant, insect repellent is still the best overall defense
against those “less savory insect and mite biters.”

“I always suggest people keep a bottle or can of repellent just outside
their doorway to remind them to spray exposed skin, even if they plan to be
outside just a short while,” he said. “Keeping repellent in your car is
a very good idea too.”

The entomologists agreed that repellents with DEET remain the gold standard
for protection.

“DEET has some of the best persistence. However, there are good
alternatives to DEET if you aren’t going to be outside very long,”
Merchant said. “The natural repellent, oil of lemon eucalyptus, is a good
alternative to DEET for those who prefer an organic product. The most
important thing is to find a repellent that works for you and to use it.”

Merchant periodically posts news updates on mosquito activity on his City
Bugs website, http://citybugs.tamu.edu[4]. He also has developed four
short videos on different aspects of mosquito control that can be found at
http://bit.ly/1F8cZkg[5].

* By: Paul Schattenberg, 210-859-5752, paschattenberg@ag.tamu.edu * By: Steve Byrns, 325-653-4576, s-byrns@tamu.edu * Contacts: Dr. Sonja Swiger, 254-968-4144, slswiger@ag.tamu.edu * Dr. Mike Merchant, 972-952-9204, m-merchant@tamu.edu * Dr. Charles Allen, 325-653-4576, ctallen@ag.tamu.edu