Neem is a fast-growing tree that can reach a height of 15-20 m (about 50-65 feet), rarely to 35-40 m (115-131 feet). It is evergreen, but in severe drought it may shed most or nearly all of its leaves. The branches are wide spread. The fairly dense crown is roundish or oval and may reach the diameter of 15-20 m in old, free-standing specimens.
NEEM Azadirachta indica
The (white and fragrant) flowers are arranged axillary, normally in more-or-less drooping panicles which are up to 25 cm (10 in.) long. The inflorescences, which branch up to the third degree, bear from 150 to 250 flowers. An individual flower is 5-6 mm long and 8-11 mm wide. Protandrous, bisexual flowers and male flowers exist on the same individual. Flowers are used to make a curry called ugadi pachadi.
(Copy from Wikipedia)
The key insecticidal ingredient found in the neem tree is
azadirachtin, a naturally occurring substance that belongs to an organic
molecule class called tetranortriterpenoids (6). It is structurally
similar to insect hormones called
Azadirachtin may also serve as a feeding deterrent for some insects. Depending on the stage of life-cycle, insect death may not occur for several days. However, upon ingestion of minute quantities, insects become quiescent and stop feeding. Residual insecticidal activity is evident for 7 to 10 days orlonger, depending on insect and application rate (1,2).
Azadirachtin is used to control whiteflies, aphids, thrips, fungus
The acute oral toxicity in rats fed technical grade azadirachtin
ranged from greater than 3,540 mg/kg to greater than 5,000 mg/kg, the
highest dose tested when administered
The acute inhalation toxicity study in rats exposed to technical
azadirachtin showed that the acute inhalation LD50 is greater than 2.41
mg/L per animal, the highest dose tested.
A primary eye irritation study in rabbits exposed to technical
azadirachtin was rated mild to moderately irritating after instillation
of 0.1 gm of the undiluted material. At one hour post-instillation, the
maximum eye irritation score was 15.3/110; by 24, 48,
Primary dermal irritation in rabbits when tested at a single dose
(0.5 gm) by applying it to the shaved backs of rabbits, did not cause
any dermal irritation after 4 hours of exposure. The dermal score was
zero for all treated rabbits at all examination times.
An acute dermal toxicity study of rabbits exposed to technical
azadirachtin was performed. The material was applied for 24 hours at a
single dose of 2.0 gm/kg to the shaved backs of the rabbits, that caused
dermal irritation which resolved by day nine.
Dermal sensitization in guinea pigs found the technical end-use product to be categorized as a mild sensitizer when administered undiluted to albino guinea pigs. The test material was considered a weak dermal sensitizer to albino guinea pigs (3).
A 90-day oral toxicity study in rats fed levels of 500, 2500, and
10,000 ppm of azadirachtin showed no signs of overt systemic toxicity at
any dose level after 90 days of feeding. Mean body weight was
significantly decreased in the 10,000 ppm males and
Male antifertility activity of neem leaf extract was studied in mice,
rats, rabbits and guinea pigs by daily oral feeding of a cold-water
extract of fresh green neem leaves. The
During this period there was no decrease in body weight and no other
manifestation of toxicity observed. There was a marked decrease in the
mortality of spermatozoa. The
No information was found.
Technical azadirachtin was evaluated for the potential to cause gene
mutations in the S. typhimurium strains at any dose (5, 50, 500, 5,000
micrograms/plate) with or without S-9
No information was found.
Fate in Humans and Animals
No information was found.
Effects on Birds
No significant effects on other wildlife were reported
Effects on Aquatic Organisms
The LC50 for rainbow trout exposed to azadirachtin is 0.48 ppm (11).
It may cause
Effects on Other Animals (Nontarget species)
Azadirachtin is relatively harmless to spiders, butterflies, and
insects such as bees that pollinate crops and trees, ladybugs that
consume aphids, and wasps that act as parasites on various crop pests.
This is because neem products must be ingested to be
Another study found that only after repeated spraying of highly
concentrated neem products onto plants in flower were worker bees at all
affected. Under these extreme conditions, the workers carried
contaminated pollen or nectar to the hives and fed it
A study of neem products and their effect on mortality, growth and
reproduction of earthworms in soils was conducted. Positive effects on
weight and survival were found in
No significant effects on other wildlife were reported (8).
Breakdown of Chemical in Soil and Groundwater
Potential for mobility in soil is very low for the
Breakdown of Chemical in Surface Water
A formulated product which contains the active ingredient
azadirachtin is considered a water pollutant. It breaks down rapidly (in
100 hours) in water or light, and
Breakdown of Chemical in Vegetation
Azadirachtin is considered non-phytotoxic when used as directed (2).
PHYSICAL PROPERTIES AND GUIDELINES
Azadirachtin is a tetranortriterpenoid botanical insecticide of the
liminoid class extracted from the neem tree Azadirachta indica. It is a
yellow-green powder, with a strong garlic-sulfur odor. Hazardous
combustion products include carbon monoxide and
1.Farm Chemicals Handbook. 1995. Meister Publishing Co. Willoughby,