International Journal of Tropical Insect Science (2011) 31, 225-234

Elias Nchiwan Nukenine, Clergé Tchiegang, Adela Andrine Tagne Mekouo, Katamssadan Haman Tofel, Charles Adarkwah, Daniel Obeng-Ofori and Cornel Adler (2011)
Efficacy of Calneem derived from Ghanaian neem seeds and seed oils from two locations in Cameroon against Sitophilus zeamais (Coleoptera: Curculionidae) on maize
International Journal of Tropical Insect Science 31 (4), 225-234
Abstract: Botanical insecticides are among the most promising alternatives to synthetic insecticides for stored product protection. Calneem oil from Ghana and local neem oils from two localities in northern Cameroon (Garoua and Maroua) were tested at 0 (untreated control), 2, 4, 6, 8 and 12 ml/kg, on the adult and immature stages of the maize weevil Sitophilus zeamais (Motschulsky), for mortality and reproduction inhibition. The neem oils from Cameroon were extracted using the traditional kneading method and a hydraulic press in the laboratory (refined). Maize grains were coated with the five neem seed oils (Calneem, Garoua traditional and refined, and Maroua traditional and refined, respectively) and adult mortality was recorded at 1, 3, 7 and 14 days after exposure. Within 1 day of exposure, the highest tested concentration (12 ml/kg) of Calneem, Garoua traditional, Garoua refined, Maroua traditional and Maroua refined oils caused similar weevil mortality of 86.3, 93.8, 93.8, 97.5 and 97.5%, respectively. The 24-h LC₅₀values for the oils in the same order were 7.0, 6.0, 5.0, 5.0 and 4.8 ml/kg, respectively. The lowest (2 ml/kg) and highest (12 ml/kg) concentrations of the oils suppressed progeny production by over 80 and 98%, respectively. The oils arrested the development of the hidden eggs and immature stages in the maize grains. The results suggested that neem seed oils from different localities of northern Cameroon, irrespective of the method of extraction, were effective for the protection of stored maize against S. zeamais. The promotion of natural neem seed oils as stored grain protectants in Cameroon would boost food security, alleviate poverty and reduce environmental degradation.
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Link to article at publishers website
Database assignments for author(s): Elias Nukenine, Charles Adarkwah, Cornel S. Adler, Daniel Obeng-Ofori

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Sitophilus zeamais	Maize/corn (Zea mays)	Cameroon
	Sitophilus zeamais	Stored grain	Cameroon