Effectiveness of Spinosad as a biogenic insecticide in controlling desert locust (Schistocerca gregaria Forsskål).

Desert locust, Schistocerca gregaria (Forsskål, 1775), is the most destructive migratory pest
worldwide, driven by climate change, land degradation, and regional conflicts. It forms massive swarms
which devastating entire crops and causing widespread food shortages. Current control measures depend
on traditional chemical insecticides, which have detrimental effects on human health and the
environment. In this study, we assessed the efficacy of Spinosad, a biogenic insecticide, against desert
locusts. Spinosad (Tracer® 24% SC) was applied at 65 ml/100 L against various stages of desert locust
(hoppers and adults). Under field conditions, our observations revealed that Spinosad induced a mortality
rate of 71% in adult and 67% in hopper instars (nymphs) at 96 hours post-treatment. Furthermore, we
assessed the proportional impact of contact toxicity versus stomach poisoning induced by Spinosad on
locust mortality. Our findings indicated that contact toxicity had a more pronounced effect on both adult
locusts and hoppers compared to stomach poisoning. Meanwhile, adults demonstrated greater
susceptibility to both modes of action than hoppers. Additionally, we evaluated the residual levels of
Spinosad on treated vegetation, and the data demonstrated a rapid decrease in Spinosad concentrations on
plants, starting at 4.582 mg/kg one hour after application and declining to 0.098 mg/kg by day 6 posttreatment. Considering the results obtained, Spinosad can provide effective control of desert locusts,
particularly when utilized as part of a comprehensive integrated pest management program.