9: Microbial Larvicide & Spinosyns

Hello! During Week 9, I did research surrounding the larvicide vector control method that I introduced last week. I continued my progress on the report, but I haven’t yet finished it because of the new information I’m adding each week. This report will likely remain unfinished until I don’t have time to add new information, and will only be wrapped up the final week we have for research. 

To find environmentally-safe and tested larvicides, my research this week has led me to focus on microbial larvicides and spinosyns. These are derived from bacteria that act as pesticides and target mosquito larvae. The main types used for malaria control are Bacillus thuringiensis israelensis (Bti) and Lysinibacillus sphaericus (Bs). Bti produces a toxin that interrupts the biological processes of the gut of mosquito larvae during digestion. It is highly effective against Anopheles mosquitoes that transmit malaria. The Bs type of microbial larvicide is a bacterium that produces proteins which damage the gut of mosquito larvae, resulting in their death. Environmental complications such as excess wind and rain can hinder their effectiveness, so the heavy rains that were part of the cause of the malaria outbreak in Pakistan would make matters worse for the use of microbial larvicide. 

Spinosyns, derived from the fermentation of the bacteria Saccharopolyspora spinosa, have the main active ingredient spinosyn A, which targets the mosquito nervous system and interferes with nerve cell communication. They are considered to have low impact on non-target organisms compared to traditional chemical insecticides, giving them a benefit in terms of not harming the environment. Some things to consider are that although they are safer than most insecticides, spinosyns still have the potential to harm beneficial insects like bees at higher concentrations. They can also be expensive and require frequent applications when in sunlight, requiring a much larger budget than may be available.

Thanks for reading this week’s blog! I’ll still be making progress on my report this coming week, but will leave more of that to the week after for final editing instead of slow progress during week 10. See you next week!