Who's spraying dispersants?

[Bob Hudson]

In the next few days I will post some information about how the SWCMCD works to control disease bearing mosquito's in South Walton. Notice that I said control not eradicate and that I specifically stated our mission is a health issue not a "I've been bitten" issue.

This is the first installment. Long but hopefully it will help understand that our mission is more than spray trucks riding throughout the area.

The South Walton Mosquito District’s (SWCMCD) program is based upon scientific approaches that have been incorporated into a comprehensive strategy of Integrated Mosquito Management (IMM). This management strategy includes several components that work together to accomplish effective mosquito control. Operations are directed primarily at controlling the mosquito species that are responsible for transmitting West Nile virus. The following are some of the components of the IMM strategy:


I. Mosquito Sampling and Inspection

Mosquito sampling and inspection provides data upon which all control operations are based. Without good inspection data, it would be virtually impossible to conduct an effective and efficient mosquito abatement program. Mosquito sampling methods used at the District are directed to collect data on mosquito adults and larvae. Strategies for control operations are based on the analysis of these data.


A. Adult Mosquito Inspection

Landing rates and light traps are utilized to collect data on adult mosquito activity in order to provide information on the relative abundance and distribution of species of mosquitoes in many locations throughout the parish.


1. Landing Rates

A landing rate is defined as the number of mosquitoes identified landing on a still human (inspector) in a minute time period. This sampling method is an excellent means of estimating the adult mosquito populations of many species. Landing rates are performed on a daily basis throughout the parish during the daytime. Occasionally, landing rates are performed at night to measure mosquito levels and to determine species that are more active during the night. Landing rates performed before and after adulticide treatments are an excellent means to evaluate the effectiveness of the applications.


2. Light Traps

Many mosquito species are attracted to light. The District takes advantage of this behavioral characteristic by utilizing light traps to collect mosquitoes. Light traps are mechanical devices that are permanently located at sampling stations throughout the parish. They are operated at night and the next morning an inspector collects the mosquitoes caught in the trap. This data provides the District with an estimate as to the relative abundance and the species of mosquitoes at each sampling site. Each trap is operated 1-2 times each week. Another mechanical light trap used is a Centers for Disease Control (CDC) trap that is portable and can easily be moved and stationed at many sampling locations. This trap utilizes carbon dioxide (CO2) as an attractant to enhance the collection. These traps are operated 2-3 times a week throughout the parish. CO2 baited CDC light traps also serve to evaluate adulticide treatments. In addition, these traps are used to collect live mosquito specimens that are sent to the lab to be tested for West Nile virus, St. Louis encephalitis, and eastern equine encephalitis. It is very important that the District has information as to whether or not mosquito borne viral agents are in the area. Another mosquito collection trap used is a gravid trap. These traps are primarily used to obtain information on the southern house mosquito, the primary vector for West Nile virus and St. Louis encephalitis. The majority of the mosquitoes collected in these traps would have recently taken blood meals and are seeking a place to deposit eggs. The specimens collected are then tested for the presence of West Nile virus and St. Louis encephalitis.

B. Larval Inspection

The best indication that a site produces mosquitoes is to find mosquito larvae in the water. Inspection of mosquito breeding areas is one of the most time consuming parts of the IMM program. The District regularly inspects breeding sites. The size of these breeding sites can vary from as small as 1/10 of an acre to several hundred acres. These sites include areas such as woodlands and pastures, roadside ditches, swamps, and artificial containers. When a site is observed to be breeding mosquitoes, if practical, it is treated to prevent the mosquito from reaching the adult stage. Monitoring these areas also provides the District with a forecast of the types of mosquito problems to expect in the next few days. The forecast permits the District to plan strategies and ensures that the most effective control approach is put into effect.

C. Service Requests

Service requests by area residents also provide information on larval and adult mosquito densities. A service request is filled out whenever a resident calls the District or visits our website to report a particular mosquito problem. Information is obtained from the resident regarding the address, telephone number, and type of problem. A course of action for correcting the problem is then decided. A biologist or mosquito control inspector is dispatched to investigate the problem and provide control within 24 hours or insofar as is practical.

II. Arbovirus Surveillance

Almost every year for the past 40 years there has been evidence of mosquito borne virus within South Walton County, namely West Nile virus, St. Louis encephalitis, and eastern equine encephalitis.

The District operates an ongoing program throughout the year to monitor for the presence of mosquito borne viral activity. Whenever a virus is detected in a particular area, mosquito control procedures are intensified to reduce mosquito populations in order to reduce the potential risk for humans or animals contracting encephalitis. In most cases, the arbovirus surveillance program will detect viral activity before humans or animals come down with the disease. This gives the District time to react aggressively with controls to help prevent human and animal disease. The arbovirus surveillance is accomplished by the collection of mosquito pools.

Mosquito Pools

Adult mosquitoes are collected by CO2 baited CDC light traps and gravid traps. The mosquitoes are then sorted by species and grouped in pools of not more than 50 mosquitoes. The mosquito pools are then sent to a lab for analysis. Mosquito pools are collected three times a week from many locations throughout South Walton.

Tomorrow I will explain "Source Reduction"

 

[Bob Hudson]

IS DEET SAFE ?

DEET Side Effects and Controversies

As with most chemical compounds, DEET doesn't come without warnings or side effects. First, let's take a look at how DEET affects the environment.

The U.S. Environmental Protection Agency (EPA) reregistered DEET in 1998 to ensure it conformed to today's more stringent standards (rather than the 1950s standards). Because DEET is applied to the skin and not directly on plants or wildlife, its impact on the environment is minimal. However, the EPA shows DEET as slightly toxic to birds, fish and aquatic invertebrates. It's virtually nontoxic to mammals. The EPA currently rates DEET as Toxicity Category III, the second lowest of four categories -- or "slightly toxic" [source: EPA].

So, is DEET bad for you? The answer isn't totally clear. Overuse of DEET can have lethal consequences. Even so, data from 1961 to 2002 shows only eight DEET-related deaths. Three were from deliberate ingestion, two from dermal (skin) exposure and three were children receiving heavy and frequent applications of DEET [source: ATSDR]. The EPA stresses that DEET is perfectly safe when used in accordance with the directions on the label. Incorrect application can lead to health issues such as skin irritation, disorientation, dizziness and, in extreme cases, seizures or death [source: ATSDR].

You hear rumors that DEET causes cancer. This may partly be due to the fact that people confuse DEET with DDT, a known carcinogen. In truth, scientists have not established a direct link between DEET and cancer. The Centers for Disease Control and Prevention (CDC) classifies DEET as a group D carcinogen -- meaning it's not classifiable as to human carcinogenicity. In simple terms, that means that they can't say it causes cancer, but they can't say it doesn't, either.

For at-a-glance information, the activist group Beyond Pesticides keeps its own list of documented DEET health and environmental effects:

Cancer: Not documented
Endocrine Disruption: Not documented
Reproductive Effects: Not documented
Neurotoxicity: Yes
Kidney/Liver Damage: Yes
Sensitizer/Irritant: Yes
Birth/Developmental Defects: Yes
Detected in Groundwater: Yes
Potential Leacher: Yes
Toxic to Birds: Not documented
Toxic to Fish/Aquatic Organisms: Not documented
Toxic to Bees: Not documented

That said, you're probably wondering how you can use DEET safely. DEET is an important weapon in the fight against mosquito- and tick-borne illnesses, so it's definitely got its value -- you just have to make sure you use it according to the label's directions. The U.S. Environmental Protection Agency requires companies to list precautions on their product labels. These labels provide important information on how to handle and apply the product. The following are some general guidelines about using products that contain DEET:

Don't use any product that has DEET and sunscreen mixed together. Unlike DEET, sunscreen requires frequent reapplication. DEET doesn't wear off as quickly as sunscreen, so you could end up with unsafe amounts of DEET on your skin.
Apply DEET only to exposed skin and/or clothing. Don't put DEET on skin that will be covered by clothing -- this will cause your skin to absorb the DEET.
Don't use DEET on any open wounds or rashes.
Keep DEET out of your eyes, mouth and ears.
Don't spray it directly on your face.
Avoid inhaling it.
Don't apply DEET near food or use it in enclosed areas.
Apply DEET in a thin layer -- just enough to cover your exposed skin. Avoid heavy application or oversaturation.
Once you return indoors, make sure you wash off the DEET with soap and water. It's especially important to do this if you plan to reapply the DEET later or the next day.

Is DEET safe for children?


Kids play outside a lot, and you don't want them coming in with itchy welts all over their bodies. But is it safe to cover your child's skin in DEET?

It is safe -- as long as you're careful about how you apply the chemical. When using DEET on or around children, use the following precautions:
Don't apply DEET to children under two months of age. Their skin can absorb too much of the chemical. Doctors believe that after two months of age, though, skin permeability is similar to an adult's [source: AAP].
For safety's sake, use the minimum amount possible when applying DEET to a child. This is actually a good rule of thumb for anyone using an insect repellent.
Insect repellents, like any chemical compound, should be stored away from children.
Don't let a child apply DEET -- spray it on your hands and do it for him or her. This prevents possible overuse.

 

[Teresa Cline]

Same thing for my yard, I am at a dead end, have a NO SPAY SIGN up but they go 50ft from my drive then start spraying, I feel its very wrong to not at least give me a chance to take my dogs and go inside before being doused with this crap!! I am VERY VERY unhappy about this.

I have a ton of mosquitoes AND my yard gets extra spray from the truck because they use my driveway to turn around.

Since it doesn't seem to keep away the bugs I would just as soon we discontinue spraying poison all over everything and everyone.

 

[Em]

Thanks for the info on DEET. That is why I asked Skunkape to stand down wind from me if he chooses to spray it on himself. In the days gone by, it was always recommended that DEET be sprayed on clothes, not directly on skin.

Bob, why does DEET have a warning label for people spraying, yet South Walton Mosquito Control has not announcements of when the poison spray truck is going to fog, prior to hosing people and pets with poisons?

As for the yellow flies and dog flies, DEET doesn't seem to have any affect, but spray some white vinegar on them and watch the run.

 

[30A Skunkape]

For the record, during last night's walk, zero mosquito bites and a fire fly sighting. Pleasant.

 

[Kurt]

For the record, during last night's walk, zero mosquito bites and a fire fly sighting. Pleasant.

I have not seen one in decades.

 

[Teresa Cline]

the fireflies used to put on amazing displays of twinkling light, almost magical they were so thick in the Point Washington area...not any more.

 

[ASH]

Saw fire flies near the Vue last evening in the grass alongside 30-A. Just a couple, but saw them.

 

[mputnal]

I always thought I could live with a few mosquito bites until a trip down the Green River in Utah. They were thick and everyone had lots of bites. The river had flooded creating swampy areas. For three nights I would have paid a lot of money for anything to kill those aggressive buggers (Asian Tiger Mosquito). I think the answer to our spraying may be one that can be solved with simple moderation. Problem areas get sprayed. Random spraying should be avoided unless someone calls to report above average activity. Occassional random spraying after heavy rains would be acceptable. I prefer not to contract Malaria but if we can save fireflies and other good insects with moderation then I would be all for it.

 

[passin thru]

In spite of the interesting mosquito discussion, we've still seen no reply or additional information/explanation from the original poster, re: "dispersants being sprayed in Seagrove."

It seems irresponsible & flaky to me, to put up something like that & then, after many of us have asked, to still refuse to elaborate, retract, etc.