Volcanos and Pest Control

Insecticide Resistance

The United States Department of Agriculture’s Agricultural Research Service opened up a Tick Research Laboratory (CFTRL) in Edinburg, Texas, where it was proven that ticks have become increasingly resistant to pesticides. With this increased resistance, their populations have grown, resulting in an influx in encounters with ticks and tick-borne diseases. Similarly, in 2015 a survey conducted through the University of Kentucky found that 68% of the pest control companies interviewed, all agreed that bed bugs are the most difficult pest to treat because bed bugs are increasingly becoming resistant to insecticides. Unfortunately, this same phenomenon is happening with mosquitos, which is more than just a nuisance, it’s a danger.

Mosquitos are some of the most prolific killers in all of history due to their proficiency of spreading both highly detrimental and fatal diseases such as Yellow Fever, Dengue Fever, Zika Virus, Malaria, and West Nile Virus. According to the World Health Organization, a total of roughly one million fatalities can be attributed to mosquitos yearly – 400,000 of which are typically due to malaria. Clearly, their increased resistance towards insecticides is a global health concern and, as such, the search for alternative mosquito control methods is urgent.

Perlite

Also known as volcanic glass, perlite is a kind of rock formed when lava is shot from an active volcano, rapidly cooling to a solid. This rapid cooling process traps water within the hardened structure, resulting in a glass-like appearance and feel. It is considered a silicate rock (a rock containing a high percentage of silica (Si)) and also contains between 2% to 5% water.

Perlite has many applications including use in roof insulation, fillings for masonry blocks, potting soil mixtures, filters for food and water, and even as an exfoliator in soaps. It is harmless for mammals non-combustible, and an excellent insulator for both noise and heat. Due to its various uses and properties, researchers Jean M. Deguenon, Ph.D. and R. Michael Roe, Ph.D. of North Carolina State University, began testing the possibility of using perlite for mosquito control.

Studies and Effectivity

The work of Deguenon and Roe marked the first time perlite was ever tested as a potential vector control product. It is thought to act as a powerful dehydrator for mosquitos, thereby possessing the ability to cause mosquitos to expire from lack of moisture.

In order to make the substance usable against these bloodsucking insects, they heated their samples and dried them out so they could easily be ground into a fine powder form. This new form of the perlite was called Imergard and was taken through various tests to see if it would repel and or/kill mosquitos. After conducting extensive tests, it was determined that, while Imergard did not repel mosquitos, it did prove fatal after a few hours of exposure. While that time frame may initially sound discouraging, Deguenon and Roe found that the Imergard was sticking to mosquitos following landing on a surface with the dust – meaning that one small interaction with the product would still be effective. This was “our most important finding,” Michael Rose says, “perlite was active against mosquitos, and it could be applied by simply mixing with water and spraying on a surface using spray equipment already being used for mosquito control.” Most importantly, the use of perlite is a mechanical treatment, not chemical, meaning that it would be impervious to any insecticide resistance that the mosquitos were building.

Implementation

A dossier for Prequalification as a new active ingredient was submitted to the World Health Organization in November of 2019. The decision is currently pending but will hopefully be made by the end of October 2020 which would allow for commercial release by late 2020 or early 2021. The EPA is also considering imergard as a potential biopesticide and it is currently undergoing testing for approval in the US.

Roe and Deguenon are also looking into the possibility of adjusting imergard treatments to also protect against other insects. “Possible future projects include testing imergard’s effects on other vectors such as sand flies, testing in Africa when sprayed on walls, and examining if it can control mosquitoes at the level of the whole community,” Roe explains in regard to the future of their project. “We have DOD funding to expand the use to different mosquito species and from mosquitoes to filth flies and sand flies to protect deployed troops. The use of mineral insecticides like we developed in our cotton work should be used for many different crops and will reduce the need for chemical insecticides.”

Citations

Mosquito-borne Diseases (2020) World Health Organization. Available at: https://www.who.int/neglected_diseases/vector_ecology/mosquito-borne-diseases/en/ (Accessed: October 2020).

Roche, J. (2020) Volcanic Rock Yields a New Kind of Insecticide for Mosquitoes, Entomology Today. The Entomological Society of America. Available at: https://entomologytoday.org/2020/09/02/volcanic-rock-yields-new-kind-of-insecticide-for-mosquitoes/ (Accessed: October 2020).

Velardo, M. (2017) What is Perlite?, Sciencing. Available at: https://sciencing.com/perlite-5402928.html (Accessed: October 2020).