Azadirachtin

Definition

A limonoid secondary metabolite extracted from neem seeds (Azadirachta indica) that functions as a potent insect growth regulator and antifeedant. It disrupts ecdysone synthesis and juvenile hormone balance, blocking molting and reproduction in susceptible insects without rapid knockdown toxicity. Widely used in organic agriculture and integrated pest management for its selective action against phytophagous pests and low vertebrate toxicity.

Etymology

From Azadirachta (the genus of neem) + -in suffix for chemical compounds.

Example

Azadirachtin applied to cabbage foliage reduces feeding damage by diamondback moth (Plutella xylostella) larvae and prevents pupation at sublethal doses.

Related Terms

• Ecdysone
• Juvenile hormone
• Insect growth regulator
• antifeedant
• neem
• limonoid
• Integrated Pest Management

Usage Notes

Distinguished from contact neurotoxins by its delayed, hormone-mediated mode of action; effective primarily against immature stages. Concentration and formulation vary widely in commercial products. Not a repellent in the strict sense—reduced feeding reflects physiological incapacity rather than avoidance behavior.