Stored grains are at risk from various pests, with the red flour beetle, Tribolium castaneum, standing out as one of the most common threats. Recent research has highlighted the potential use of saponin-rich extracts from quinoa husks as effective biopesticides against these pests.
The study explored the insecticidal and antinutritional properties of these extracts, noting significant mortality and reduced feeding at concentrations above 25 mg/g. Surprisingly, at this level, the beetles’ ability to consume flour plummeted, demonstrating feeding deterrent rates of around 84.20%.
Conducted by researchers at the Mohamed VI Polytechnic University in Morocco, these findings point to quinoa saponins as viable alternatives to chemical pesticides, which often come with undesirable environmental impacts and pest resistance issues. Their approach involved extracting these compounds using optimized protocols and applying them to T. castaneum through dietary inclusion and direct topical exposure.
The core of the research revolved around assessing both the immediate and long-term effects of saponin extracts on the beetles. By monitoring their survival and dietary intake, the researchers established the effectiveness of the SRE, which induced acute toxicity by damaging the insects' protective waxy cuticles.
The results of this research are encouraging—not only does SRE demonstrate acute insecticidal activity, but it also disrupts the nutritional uptake of T. castaneum, undermining its growth and survival prospects. "The findings of this study indicate saponin extract has a very interesting application as an insecticide against storage insects," the authors stated, drawing attention to the dual mechanism of action exhibited by the saponins, affecting both starvation and systemic toxicity.
The study also delves deeply on the underlying biological mechanisms, indicating how saponins interact with enzymatic activities within the beetles, substantiative for the observed effects. With documented increases or decreases seen in various enzyme functionalities post-exposure, it offers insights on how saponins could rewire the physiological responses of T. castaneum.
Given the results, quinoa saponins could contribute significantly to developing safer pest control methods for stored grains, reducing reliance on synthetic chemicals. These findings pave the way for future research to investigate the broader application of quinoa saponins and potentially other plant-based extracts, with hopes of developing integrated pest management strategies centered around sustainable practices.