Terawet Green Technologies
"Uniting Science with Nature" 
San Diego, California, USA * Kolkata, West Bengal, India
On an average 18 % of the crop yield is lost due to pest infestation.
Certain hormones are necessary for growth and development of insects. These hormones control the process of metamorphosis as the insects pass from larva to pupa to adult.
Azadirachtin is currently considered as neem’s main agent for controlling insects. It appears to cause 90% of the effect on most pests. It does not kill insects – at least not immediately – instead it both repels and disrupts their growth and reproduction.
Research over the past years has shown that it is the most potent growth regulator and feeding deterrent ever assayed. It will repel or reduce the feeding of many species of pest insects as well as some nematodes. In fact, it is so potent that a mere trace of its presence prevents some insects from even touching plants.
Azadirachtin blocks those parts of the insect’s brain that produce these vital hormones. As a result, insects are unable to molt.
It is through these subtle hormonal effects that this important compound of neem breaks the life cycle of insects. The insect populations decline drastically as they become unable to reproduce.
The neem products especially azadirachtin enter into the body of larvae and the activity of ecdysone enzyme is suppressed, the larva fails to molt, remains in larval stage and ultimately dies.
If larva manages to enter the pupal stage due to low azadirachtin concentration it dies and still at low concentration of azadirachtin, the adult emerging from the pupa is 100 % malformed, absolutely sterile without any capacity for reproduction.
Blocking the larvae from molting is considered to be neem’s most important quality, which can be used to eliminate many pest species.
Meliantriol and salannin act as powerful anti-feedants.
Nimbin as well as nimbidin (another neem component) have antiviral property.
For all the uncertainty over details, various neem extracts are known to act on various insects by:
- Disrupting or inhibiting the development of eggs, larvae or pupae
- Blocking the molting of larvae or nymphs•Disrupting mating and sexual communication
- Repelling larvae and adults
- Deterring females from laying eggs
- Sterilizing adults
- Poisoning larvae and adults
- Deterring feeding
- Blocking the ability to “swallow” (that is, reducing the motility of the gut)
- Sending metamorphosis awry at various stages
- Inhibiting the formation of chitin.
All these effects listed above are not equally strong or certain.
Neem products are harmless to most insect eaters, humans and other mammals, except certain marine life like crabs, lobsters, fishes and tadpoles.
Neem has an advantage over the currently used pesticides.
Unlike chemical insecticides, neem compounds work on the insect’s hormonal system, not on the digestive or nervous system and therefore does not lead to development of resistance in future generations.
These compounds belong to a general class of natural products called ‘limonoids’.
The liminoids present in neem make it a harmless and effective insecticides, pesticide, nematicide, fungicide etc. The most significant liminoids found in neem with proven ability to block insect growth are: azadirachtin, salanin, meliantriol and nimbin.
