Studies on neem Azadirachta indica A. Juss in Malaysia

Loke W.H., . and Heng C.K., . and Azman Rejab, . and Norlaili Basirun, . and Hanisah Che Abas, . (1990) Studies on neem Azadirachta indica A. Juss in Malaysia. [Proceedings Paper]

Neem Azadirachta indica A. Juss a native tree of the Indian Sub-continent can be found in all states of Malaysia. The highest population of trees over 2500 are found in Penang while Kelantan and Trengganu have the least trees. Most of the trees are planted along road sides as shade/ornamental trees with the rest grown in compounds of houses and Indian temples for medicine/religious purposes. Two flowering-fruiting seasons-a main season with flowering in February-April and fruit ripening in June-August and a minor season with flowering in July-September and fruit ripening in October-December were observed. Six concentrations 1.25 2.5 5 10 20.0 and 40.4 percent of neem oil in acetone were evaluated for contact toxicity against second and third larval instars of Plutella xylostella L. Significant mortalities of both larval stages were observed with neem oil concentrations of 10 percent and above. Although the lower neem oil concentrations appeared to be sublethal with regard to contact toxicity effect physiological and growth disruptive effects such as retardation of growth prolonged larva stadia delayed adult emergence and abnormal adults were observed. The effects were more pronounced in the younger instar. Subsequent treatments of pupae and adults of P. xylostella with neem ooil concentrations of 1.25 2.5 5 and 10.0 percent showed that pupae were generally not affected by the concentrations tested. However male and female adult moths treated with 2.5 percent and higher concentrations of neem oil had significantly higher 48-h mortalities and shorter longevities than control adults. Using a leaf disc technique it was shown that concentrations of neem oil at 1.25 percent and bove deterred feeding of P. xylostella larvae substantially as compared to lower concentrations of neem oil at 1.25 percent and bove deterred feeding of P. xylostella larvae substantially as compared to lower concentrations and control acetone. Neem oil was also found to possess ovicidal properties. Concentrations above 1.25 percent significantly reduced egg hatch while at 20.0 percent all treated eggs were damaged and did not hatch at all

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Abstract

Neem Azadirachta indica A. Juss a native tree of the Indian Sub-continent can be found in all states of Malaysia. The highest population of trees over 2500 are found in Penang while Kelantan and Trengganu have the least trees. Most of the trees are planted along road sides as shade/ornamental trees with the rest grown in compounds of houses and Indian temples for medicine/religious purposes. Two flowering-fruiting seasons-a main season with flowering in February-April and fruit ripening in June-August and a minor season with flowering in July-September and fruit ripening in October-December were observed. Six concentrations 1.25 2.5 5 10 20.0 and 40.4 percent of neem oil in acetone were evaluated for contact toxicity against second and third larval instars of Plutella xylostella L. Significant mortalities of both larval stages were observed with neem oil concentrations of 10 percent and above. Although the lower neem oil concentrations appeared to be sublethal with regard to contact toxicity effect physiological and growth disruptive effects such as retardation of growth prolonged larva stadia delayed adult emergence and abnormal adults were observed. The effects were more pronounced in the younger instar. Subsequent treatments of pupae and adults of P. xylostella with neem ooil concentrations of 1.25 2.5 5 and 10.0 percent showed that pupae were generally not affected by the concentrations tested. However male and female adult moths treated with 2.5 percent and higher concentrations of neem oil had significantly higher 48-h mortalities and shorter longevities than control adults. Using a leaf disc technique it was shown that concentrations of neem oil at 1.25 percent and bove deterred feeding of P. xylostella larvae substantially as compared to lower concentrations of neem oil at 1.25 percent and bove deterred feeding of P. xylostella larvae substantially as compared to lower concentrations and control acetone. Neem oil was also found to possess ovicidal properties. Concentrations above 1.25 percent significantly reduced egg hatch while at 20.0 percent all treated eggs were damaged and did not hatch at all

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Item Type:	Proceedings Paper
Additional Information:	6 tables 4 ref.; Summary En
AGROVOC Term:	AZADIRACHTA INDICA
AGROVOC Term:	MALASIA
AGROVOC Term:	PLUTELLA XYLOSTELLA
AGROVOC Term:	INSECTICIDAS DE ORIGEN VEGETAL
AGROVOC Term:	PLAGUICIDAS DE ORIGEN VEGETAL
Geographical Term:	MALAYSIA
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:26
URI:	http://webagris.upm.edu.my/id/eprint/14921

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