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Dr. R. C. Saxena of International Centre of Physiology and Ecology, Manila, Philippines, is fully convinced about ESSENTIALITY OF NEEM EXTRACT for Rice culture and has contributed his findings on Neem ectract to a number of International forums. According to him, "Neem extract is a contact and volatile ovipositional deterrent............ is potential Anti-Feedant against Insect pests of Rice like Brown plant hopper, Green leaf hopper, Sogatella; Virus transmission is reduced and the product is safe for environment."
Dr. S. E. Reynolds and K.D. Wing of University of Bath, U.K., have done work on Neem tree products and have discovered that, "A Triterpenoid from Neem tree inhibits feeding, disrupts ecdysis in Meduca caterpillar. The terpenoid, Azadirachtin, is a powerful growth regulator of insect pests and an ideal tool to thwart their growth and reproduction."
In one of the oldest and most respected Research Institutes in India, Research is being done on Neem extracts. Dr. S. R. Chavan of Dept. of Phytochemistry, Haffkine Institute, Bombay has isolated from Neem leaves, alkanes which gave 100% mortality at 10 ppm concentration for 5 days on Culex mosquitoes.
Dr. S. Pradhan and Dr. M.G. Jotwani of Indian Agricultural Research Institute, New Delhi, have studied various parts of Neem plants and have found Anti-Feedant and Repellent activity of the extracts. High degree of Anti-Feedant activity was found against the Desert locust, Schistocera gregaria. Anti-Feedant properties have been determined by them against several field pests, including Spodoptera litura, Euproctis lunata, Acrida exaltata. In recent field trials, they have found granular formulations of Neem kernel effective against Corn and Sorghum stem borers. The Juvenilizing effect of Azadirachtin on Spodoptera litura has been reported recently by Entomology Division of Indian Agricultural Research Institute, New Delhi.
West Germany is one of the world’s leading Countries doing research on Neem. Dr. K. Ermel and Dr. E. Pahlich, of Justus Liebig University, Giessen, FRG, have found that extracts of seed kernels from India gave the best yields of Azadirachtin, Whereas those of Sudanese origin gave lowest amounts. They also correlated growth regulating efficacy with Azadirachtin in trials with Aedes aegypti and Epilachna varivestis as test insects.
In Thailand kasetsart University of Bangkok is undertaking the work on effects of Neem extracts on Insect pests of economic importance in Thailand. Their Scientists found no egg deposition of the Oriental Fruit fly, Dacus dorsalis, for 2 days on Banana after Neem extract treatment. The dreaded Insect Diamond back moth, Plutella larvae were treated with 0.1% Neem kernel extract and it was found that survival rate, to adult stage, dropped sharply (0%-21%)
Dr. H. Rembold and H. Forster of Max Planck Institute of West Germany have isolated Azadirachtin from Neem (Azadirachta indica). The substance was found to inhibit egg development and prevent moulting. The half life of the active principal was more than a week. In mainland china, the search for environmentally sound methods of controlling Insect pests is underway for many years. The results indicate that polar components are systemic in action while others have Anti-Feedant activity. Results of Azadirachtin were positive against Nilparvata lugens, Orseolia oryzae (Gallmidge). International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad India, have undertaken work on bio-assay of solvent extracts of Neem tree and have found that the treated larvae of Oriental army worm on Sorghum could not pupate.
BIBLIOGRAPHY AND REFERENCE OF NEEM :
1. Jacobson, M. (1986) 3rd Intern. Work, Conf. Stored Prod. Entomol, Kansas.
2. Ascher, K.R.S. (1983) Pros. 1st Int. Neem Conf. Rottach- Egern,
FRG: 63 -74.
3. Fagoonee, I (1980) proc. Isst. Int. Neem, Conf. Rottach-Egm: 109 -120.
4. Chiu, S.F. (1984), Proc. II Int. Neem Conf. FRG.
5. Lewis, W. H. and Elvin - Lewis , M.P.E. (1983) Eco. Bol. Vol. 37 (1) : 69 -70
6. Schmutterer, H.(1984) Mitteil, ungin aus der Sio, sound. fur and forst Berlin- Dahlem: 233-333.
7. Karim, A. (1980) Proc. 1st Inter, Neem Conf. Rottach - Egern., FRG : 223 - 250.
8. Meisner, I; kehi, M; Zur, M. and Eizick (1978) Phytoparositica vol. 6:85-88.
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