If you are new to Louisiana (or the south in general) like I am, you may have wondered: “What are those trucks that drive around at night spraying some unknown chemical substance into the air I breathe?” This was a completely foreign concept to me as a native of Michigan because you never see a truck equipped with a sprayer full of insecticide driving around town. For those curious about mosquito control in southern Louisiana, I thought I would introduce you to your friendly neighborhood “bug-busters” that work tirelessly to defend you from those backyard pests that never receive an invite to your house party, but insist on showing up anyway.
I attended a lecture given by one of Lafourche Parish’s own “bug guys.” Steve Pavlovich, entomologist and General Manager of Mosquito Control Inc., happens to know all about mosquitoes and ways to control their populations. Pavlovich initially went to medical school, but later switched career paths and entered the world of insect biology. During his lecture, he went into great detail about the current mosquito control program in Lafourche Parish, as well as other areas in Louisiana.
How do the “bug guys” protect southern Louisiana from the bloodsuckers that invade our territory? They have established a five-part program to control mosquito populations. Pavlovich stressed the importance of inspection and surveillance to a successful mosquito control program. This allows the scientists to determine specific locations to focus on for control. It is based on the amount of mosquitoes, as well as the presence of particular species of mosquitoes that are vectors for diseases we have all heard about from the media such as Dengue Fever, West Nile Virus and, everyone’s new favorite, Zika Virus. Once problem areas have been identified, different methods of control can be used.
My major concern has always been the chemicals used to reduce mosquito populations. How long do they last in the environment and how might these substances harm other organisms? Pavlovich shared that the chemicals used are light, don’t build up, only last in the environment for a few hours and are highly target specific, meaning they mostly only negatively impact certain species of mosquitoes. Also, only a small amount of the chemical can actually be sprayed at a time to prevent a build up of chemicals in the area. A maximum amount of chemical sprayed and a rotation of the types of chemicals used can prevent the mosquitoes from building a tolerance that allows them to survive the chemical spray. This is especially important for the mosquitos that harbor the diseases we all fear. Although regulations are put in place to limit the negative impact the chemicals have on the environment and organisms other than the target mosquitoes, there is still the issue of the chemicals affecting other insects in the area. In the future, I believe the use of biological controls (use of natural predators) for mosquito populations would be more effective and less harmful to the environment than the common chemical controls like those spray trucks we all know and love.
One of the most interesting things Pavlovich shared was the use of a biological control in the form of bacterial products made from naturally occurring soil bacteria (Bacillus sphaericus and Bacillus thuringiensis israelensis), which are very specific to targeting mosquito larvae. These products are sprayed into water systems where mosquito larvae are present. They are so effective that they typically kill the mosquito within two to three hours by attacking the stomach and causing internal bleeding (Federici 2007). These products have so many toxins in them that there has yet to be a case of a mosquito building up a tolerance against these bacterial products to allow them to resist its effects. These products are now being used worldwide and no harmful environmental impacts from the bacteria have been recorded (De Barjac and Sutherland 2012). The best part about these products is they have no negative effect on humans, domestic animals, or even other aquatic insects. With more research, I believe other successful controls that involve natural, native organisms as a form of mosquito control can be developed without bringing harmful consequences to the environment.
By A. Ostrowski
De Barjac, Huguette, and Donald J. Sutherland, eds. Bacterial Control of Mosquitoes & Black Flies: Biochemistry, Genetics & Applications of Bacillus Thuringiensis Israelensis and Bacillus Sphaericus. Springer Science & Business Media, 2012.
Federici, Brian A., et al. “Developing recombinant bacteria for control of mosquito larvae.” Journal of the American Mosquito Control Association23.sp2 (2007): 164-175.