n African Entomology - Laboratory evaluation of bioactivity of ethanolic extracts of plants used for protection of stored maize against Sitophilus zeamais Motschulsky in Cameroon
|Article Title||Laboratory evaluation of bioactivity of ethanolic extracts of plants used for protection of stored maize against Sitophilus zeamais Motschulsky in Cameroon|
|© Publisher:||Entomological Society of South Africa (ESSA)|
|Author||C.A. Akob and F.K. Ewete|
|Publication Date||Mar 2009|
|Pages||90 - 94|
|Keyword(s)||Bioactivity, Cupressus arizonica, Eucalyptus grandis, Ocimum gratissimum, Sitophilus zeamais and Vetiveria zizanioides|
The maize weevil, Sitophilus zeamais Motschulsky (Coleoptera : Curculionidae), is an important cause of stored maize losses in the Western highlands of Cameroon. Chemical insecticides for rapid control are expensive and not readily available. In search for cheap and easily available natural products to control this insect pest, the biological activity of ethanolic extracts of some traditionally used plant materials were evaluated against the weevil. Laboratory studies on toxicity against F1 progeny, contact toxicity and repellency against S. zeamais were conducted with ethanolic extracts of Vetiveria zizanioides roots, and Cupressus arizonica, Ocimum gratissimum, Eucalyptus grandis leaves. The ethanolic extracts of the last three plant species had significant toxicity (P = 0.01) on S. zeamais and against the F1 progeny. Percentage repellency was significant across the four plant extracts but highest in grains treated with V. zizanioides. Repellency was concentration-dependent and greater than 50 % at the lowest V. zizanioides extract concentration of 12 500 ppm. Vetiveria zizanioides could be a potential repellent for the protection of stored products against S. zeamais.
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