Azadirachtin, a chemical compound belonging to the limonoid group, is a secondary metabolite present in Neem seeds. It is a highly oxidized tetranortriterpenoid which boasts a plethora of oxygen functionality, comprising enol ether, acetal, hemiacetal, and tetra-substituted oxirane as well as a variety of carboxylic esters.
It was initially found to be active as a feeding inhibitor towards the desert locust(Schistocerca gregaria), it is now known to affect over 200 species of insect, by acting mainly as an antifeedant and growth disruptor, and as such it possesses considerable toxicity toward insects (LD50(S. littoralis): 15 μg/g). It fulfills many of the criteria needed for a natural insecticide if it is to replace synthetic compounds. Azadirachtin is biodegradable (it degrades within 100 hours when exposed to light and water) and shows very low toxicity to mammals (the LD50 in rats is > 3,540 mg/kg making it practically non-toxic).
This compound is found in the seeds (0.2 to 0.8 percent by weight) of the neem tree,Azadirachta indica (hence the prefix aza does not imply an aza compound, but refers to the scientific species name). Many more compounds, related to azadirachtin, are present in the seeds as well as in the leaves and the bark of the neem tree which also show strong biological activities among various pest insects. Effects of these preparations on beneficial arthropods are generally considered to be minimal. Some laboratory and field studies have found neem extracts to be compatible with biological control. Because pure neem oil contains other insecticidal and fungicidal compounds in additional to azadirachtin, it is generally mixed at a rate of 1 ounce per gallon (7.8 ml/l) of water when used as a pesticide.
It was initially found to be active as a feeding inhibitor towards the desert locust(Schistocerca gregaria), it is now known to affect over 200 species of insect, by acting mainly as an antifeedant and growth disruptor, and as such it possesses considerable toxicity toward insects (LD50(S. littoralis): 15 μg/g). It fulfills many of the criteria needed for a natural insecticide if it is to replace synthetic compounds. Azadirachtin is biodegradable (it degrades within 100 hours when exposed to light and water) and shows very low toxicity to mammals (the LD50 in rats is > 3,540 mg/kg making it practically non-toxic).
This compound is found in the seeds (0.2 to 0.8 percent by weight) of the neem tree,Azadirachta indica (hence the prefix aza does not imply an aza compound, but refers to the scientific species name). Many more compounds, related to azadirachtin, are present in the seeds as well as in the leaves and the bark of the neem tree which also show strong biological activities among various pest insects. Effects of these preparations on beneficial arthropods are generally considered to be minimal. Some laboratory and field studies have found neem extracts to be compatible with biological control. Because pure neem oil contains other insecticidal and fungicidal compounds in additional to azadirachtin, it is generally mixed at a rate of 1 ounce per gallon (7.8 ml/l) of water when used as a pesticide.