Tritschler, K. (2025). Natural pesticides: Assessing the influence of salinity stress and mitigation via B. subtilis application on the development of lamiaceae botanicals and their impact on the natural predator H. convergens. The Young Researcher, 9(1), 147-163. http://www.theyoungresearcher.com/papers/tritschler.pdf

Abstract
Botanicals are plant extracts created for pest deterrence. While this potential has been thoroughly verified, prior research has seldom investigated how their suitability is impacted by abiotic stressors, nor how they may impact non-target species exposed to them. This research investigates how salinity stress, and mitigation via B. subtilis application, impacts this suitability. It was hypothesized that higher salinity would lead to stronger pest deterrence, based on prior literature correlating salinity stress with increased monoterpenoid production. The results showed trivial (η < 0.1, p < .001) impacts to plant growth under higher salinity levels; the application of Bacillus subtilis had significant species-dependent influences. Regarding the deterrence of the natural predator Hippodamia convergens, the results found no discernable sublethal trends regarding salinity, and a correlation with a slower time of death. The commercial pesticide λ-cyhalothrin showed similar lethality compared to the botanical treatments, raising concerns regarding botanicals’ toxicity to non-target organisms.

Keywords: Botanicals, Pesticide, Salinity Stress, H. convergens, Lamiaceae

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