Isolation of Bioactive Fumigants from Different Varieties of Cassava (Manihot esculenta Crantz) and their Toxicity on Tribolium castaneum Herbst and Rhyzopertha dominica Fabricius

Tribolium castaneum Herbst and Rhyzopertha dominica Fabricius are significant pests causing both qualitative and quantitative deterioration of stored products. The reliance on synthetic fumigants to control these pests poses numerous risks to human health and the environment. Given cassava's status as a cyanogenic plant, this study screened nine cassava varieties to isolate insecticidal compounds effective against stored product pests. Both young and mature leaves were subjected to hydrogen cyanide extraction, a potential fumigant approved by the Central Insecticidal Board (CIB) of India. Extraction was performed using two methods: direct leaf crushing at room temperature and mechanical extraction with a biopesticide extraction plant at ICAR-Central Tuber Crops Research Institute. Among the varieties, Sree Swarna exhibited the highest cyanogen content, while Sree Jaya had the least. Laboratory assays demonstrated that R. dominica was more susceptible to the cassava-derived bio-fumigant than T. castaneum. These findings suggest that bio-fumigants from cassava leaves are a viable alternative to synthetic fumigants for managing stored product pests.