Resource Guide for Organic Insect and Disease ... - Cornell University

MATERIAL FACT SHEET
Neem (azadirachtin, neem oil, neem oil soap)
136 Organic Resource Guide
MATERIAL NAME: Neem (azadirachtin, neem oil, neem oil soap)
MATERIAL TYPE: Botanical
U.S. EPA TOXICITY CATEGORY: III, “Caution” (Neemix carries a “Warning” signal word)
USDA-NOP:
Considered a non-synthetic, botanical pesticide; its use is regulated. Preventive, cultural, mechanical,
and physical methods must be first choice for pest control, and conditions for use of a
biological material must be documented in the organic system plan (NOP 2000).
MATERIAL DESCRIPTION:
Neem products are derived from the neem tree, Azadiracta indica. The neem tree is native to
southern Asia and can grow in most arid, sub-tropical, and tropical areas of the world (Copping
2001). Called Sarva Roga Nirvani, a “cure of all ailments” in Sanskrit, neem has been used for
centuries for medical, cosmetic, and pesticidal purposes. Although Indian scientists were researching
the use of neem as early as the 1920s, there was little global attention until a German
entomologist noticed, in 1959, that neem trees in the Sudan resisted an attack of migratory
locusts. Since that time, there has been considerable research and commercialization of neem
products (Ruckin 1992).
Neem pesticide products are usually made by crushing neem tree seeds, and then using water
or a solvent, such as alcohol, to extract the pesticidal constituents. Other products are made
from cold-pressed neem seed oil or from further processed neem oil. Neem products produced
with different extraction techniques may result in different biologically active chemicals
(or amounts of chemicals) in a product; thus, the efficacy of different products can be highly
variable. Neem cake is the residual seed meal remaining after extraction of oil from seeds; it is
often sold as a fertilizer product.
Neem products can be grouped into two classes:
Azadirachtin-based products
Includes AZA-Direct, Azatrol, Neemix.
Neem oil products
Trilogy (also packaged as Triact, Green Light Neem Concentrate, and Green Light Rose Defense)
is neem oil that has had the azadirachtin and at least some other components separated from
it. It is called “clarified hydrophobic extract of neem oil.” One hundred percent cold pressed
neem oil is also being sold as a “plant wash,” but has no pesticide label.
HOW IT WORKS:
Pesticide active ingredients are based on neem seed extracts, including azadirachtin, neem oil,
and neem oil soap. Azadirachtin, one of the more than 70 compounds produced by the neem
tree, acts mainly as an insect growth regulator, but also has anti-feedant and oviposition (egglaying)
deterrent properties. First isolated in 1968, azadirachtin is thought to be the most bioactive
ingredient found in the neem tree; however, such speculation may be due to it having
been investigated more thoroughly then the other compounds (Thacker 2002; Quarles 1994).
Most commercially available neem products list azadirachtin as the primary active ingredient.
Such products are broad-spectrum insecticides, which work by contact or ingestion. As an
insect growth regulator, azadirachtin prevents insects from molting by inhibiting production of
ecdysone, an insect hormone. Azadirachtin is chemically similar to ecdysonlids, the hormones
responsible for triggering molts (Weinzierl & Henn 1991). As an anti-feedant, after ingestion, it