azadirachtin

Azadirachtin is a group of highly potent insecticidal compounds, mainly azadirachtin A and azadirachtin B, within the neem tree (Azadirachta indica). It is a limonoid produced in seeds and other parts of the plant. The azadirachtins comprise the principal active constituents of neem seed extracts and are used as natural pesticides in organic agriculture.

Azadirachtin acts primarily as an antifeedant and insect growth regulator. It disrupts feeding behavior and interferes with insect molting and development by affecting hormonal signaling, particularly ecdysone pathways. The result is reduced growth, sterility, or death of susceptible stages. The spectrum includes many herbivorous insects; effectiveness varies by species and formulation.

Used in various formulations (emulsifiable concentrates, wettable powders, granules, and oils) marketed for home gardens and commercial agriculture. It is valued for being biodegradable and compatible with integrated pest management. It is often used against caterpillars, aphids, whiteflies, and beetles, among others, but is not universally effective and may require repeated applications or combination with other controls.

Commercial azadirachtin is extracted from neem seeds or seed kernels by solvent or supercritical methods. Yields and stability vary; azadirachtins are sensitive to light, heat, and oxygen, so formulations include UV stabilizers and carriers to extend shelf life. The compound is usually more effective as part of a broader IPM program than as a stand-alone solution.

Azadirachtin exhibits low acute toxicity to mammals, birds, and fish in standard tests, but may irritate skin and eyes and can be hazardous to aquatic organisms; regulatory status varies by country. It is widely registered for use in organic farming, with labels specifying application rates, target pests, and water-quality precautions.