Larvicidal activity of Neem oil and three plant essential oils from Senegal against Chrysodeixis chalcites (Esper, 1789)

ABSTRACT

Objective:To evaluate the insecticide,larvicidal and repellent activity of the essential oils from Callistemon vimindis,Melaleuca leueadendron,and Hyptis suaveolens against Chrysodeixischalcites and to compare it with neem oil (Azadirachta indica).Methods:The essential oils of the leaves of these aromatiques plants were extracted by steam distillation and contacts tests were carried out.Results:Essential oils in ethanol from Callistemon viminalis showed a higher biological activity than the neem with 100％ larval mortality at the concentration of 2 μg/mL for 6 h,100％ and 90％ in ethanol from Melaleuca leucadendron and Hyptis suaveolens,respectively at the concentration of 4 μg/mL for 24 h.By inhalation,the essential oils from Melaleuca leucadendron and of Hyptis suaveolens were more effective with mortality rates of larvae 100％ and 50％ respectively at 2 μg/L air applied after 24 h.Nevertheless,the neem has shown to be a repulsive plant and anti-nutritional plant.A significant difference in the percentages of consumption between leaves treated with neem oil and the control samples was observed (Newman-Keuls test) except for Melaleucaleucadendron.Conclusions:The results of the study highlight remarkable biocide,properties of tested extracts,which provides important opportunities for the development of biopesticides.