Efficacy of plant extracts against the cowpea beetle, Callosobruchus maculatus

• Published in: International journal of pest management Vol. 50; no. 4; pp. 251 - 258
• Main Authors: Boeke, S.J, Barnaud, C, Loon, J.J.A. van, Kossou, D.K, Huis, A. van, Dicke, M
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Ltd 01.10.2004; Washington, DC Taylor & Francis
• Subjects: Azadirachta indica; Biological and medical sciences; Biological control; botanical insecticides; Callosobruchus maculatus; Coleoptera; Control; cowpeas; Cymbopogon citratus; Cymbopogon flexuosus; Cymbopogon nardus; extracts; fecundity; Fundamental and applied biological sciences. Psychology; Hyptis spicigera; insect control; insect development; insect repellents; Life Sciences; life-history; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; Ocimum basilicum; oils; Pests of stored products; Phytopathology. Animal pests. Plant and forest protection; piper-guineense; plant fats and oils; products; protectants; Protozoa. Invertebrates; repellence; repellency; storage insects; stored cowpea; stored product pests; stored product protection; Tephrosia; toxicity; Vigna unguiculata, olfactometer; volatile compounds; Life history; Coleoptera; Toxicity; Insecta; Pest and disease control; Vigna unguiculata; Repulsive activity; Cowpea; Botanical insecticide; repellence; botanical insecticides; Callosobruchus maculatus; Leguminosae; life-history; Arthropoda; Dicotyledones; Angiospermae; Bruchidae; Spermatophyta; extracts; Biopesticide; Invertebrata; Olfactometer; stored product pests; toxicity; botanical; olfactometer; coleoptera; vigna unguiculata; insecticides
• ISSN: 0967-0874; 1366-5863
• DOI: 10.1080/09670870410001702206

Traditionally used African plant powders, with a known effect against the cowpea beetle Callosobruchus maculatus in stored cowpea, were extracted with water. The extracts, 13 volatile oils, 2 non-volatile oils and 8 slurries, were evaluated for their toxic and repellent effects against the beetle. Application of volatile oils led in most cases to a reduced number of eggs on treated beans. The volatile oils of Cymbopogon nardus and C. schoenanthus caused the majority of the eggs not to develop into adult beetles. Repellent effects were found for Clausena anisata, Cymbopogon citratus, Cymbopogon nardus, a mixture of Cymbopogon citratus and Cymbopogon flexuosus, Hyptis spicigera, Tagetes minuta and for two samples of Ocimum basilicum. Non-volatile oils were not repellent and had no effect on the number of eggs laid, but the development of these eggs was hampered, most so by Azadirachta indica oil. None of the slurries had a toxic effect on the beetles, but the slurries obtained from Carica papaya, Dracaena arborea and Tephrosia vogelii were repellent, whereas the slurry from Azadirachta indica leaves was attractive. Oils, both volatile and non-volatile, were easily extracted from plant material and showed promising results as a protective agent for stored cowpea.