Toosendanin-based botanical insecticide from melia volkensii for stored grain and crop pest management

Overview

This solution harnesses toosendanin, a triterpenoid phytochemical naturally produced in the nuts of Melia volkensii, a tree native to Kenya. The research focuses on developing a standardized extraction method and a practical formulation, using adjuvants such as kaolin, that delivers reliable pest control while being safe for application on grain intended for human consumption. The product is positioned as a safer alternative to existing Kenyan grain dusts, which rely on organophosphates combined with synthetic pyrethroids.

The target pests include the maize weevil (Sitophilus zeamais), a major threat to stored grain, and lepidopteran larvae such as fall armyworm (Spodoptera frugiperda), which damages maize and other crops in the field. By replacing synthetic chemistries with a bio-based active ingredient, the solution addresses growing concerns over chemical residues, pest resistance, and worker safety in post-harvest and crop protection.

Technical specifications

Active ingredient and source:

• Toosendanin, a triterpenoid compound isolated from Melia volkensii nuts
• Raw material sourced from trees growing across diverse Kenyan ecologies, with potential variations in concentration and potency to be characterized

Mode of action:

• Insecticidal activity against stored-grain weevils and lepidopteran larvae
• Induces cell damage in target pests, providing a biological mechanism distinct from conventional neurotoxic grain protectants

Formulation approach:

• Kaolin-based adjuvants to develop a grain-safe dust formulation
• Designed for compatibility with stored grain intended for consumption
• Standardized extraction protocol to ensure consistent yield and potency of the active phytochemical

Research focus areas:

• Optimization of extraction methods across varied M. volkensii ecologies
• Safety assessment for use on food grain
• Efficacy validation against Sitophilus zeamais and Spodoptera frugiperda

Technology readiness level

The technology is at an early-to-mid research and development stage. Current work centers on establishing a reproducible extraction process, formulating a kaolin-based grain dust, and conducting initial efficacy and safety evaluations against target pests. Validation procedures and future validation plans are in progress to confirm insecticidal performance, formulation stability, and food-grain safety. Further field and storage trials will be required to advance toward commercial deployment.