Seed Yield Improvement in Vigna unguiculata (L.) (Fabaceae): Efficiency of Pollinators and Impact of Aqueous Leaf Extract of Three Plant Species in North Cameroon
M. Mohammadou
Zoology Unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, P.O. Box-24157, Douala, Cameroon, Laboratory of Applied Zoology, Department of Biological Sciences, Faculty of Science, University of Ngaoundere, P.O. Box-454 Ngaoundere, Cameroon and Faculty of Medicine and Biomedical Sciences, University of Garoua, P.O. Box-317, Garoua, Cameroon.
M. Adamou
Laboratory of Applied Zoology, Department of Biological Sciences, Faculty of Science, University of Ngaoundere, P.O. Box-454 Ngaoundere, Cameroon and Faculty of Medicine and Biomedical Sciences, University of Garoua, P.O. Box-317, Garoua, Cameroon.
Taïmanga
Department of Agronomy, Institute of Fisheries and Aquatic Sciences, University of Douala, P.O. Box-2701 Douala, Cameroon.
D. Kosini
Faculty of Medicine and Biomedical Sciences, University of Garoua, P.O. Box-317, Garoua, Cameroon.
M. Kenne *
Zoology Unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, P.O. Box-24157, Douala, Cameroon.
*Author to whom correspondence should be addressed.
Abstract
Aims: Because of the problems in agroecosystems following the anarchic use of synthetic insecticides, studies propose an alternative, the use of botanical biopesticides against pests.
Study Design: The present study was conducted to evaluate (1) the potential of leaf extract of Calotropis procera (Gentianales: Apocynaceae), Eucalyptus camaldulensis (Myrtales: Myrtaceae) and Tithonia diversifolia (Asterales: Asteraceae) against insects and (2) impact of Apis mellifera (Hymenoptera: Apidae) on Vigna unguiculata (Fabales: Fabaceae) seed yield in North Cameroon.
Place and Duration of Study: A field study was set up in 2021 in North Cameroon, during the rainy season. Fourthy four plots of 4x3.5 m each were distributed according to a randomized complete block design model comprising four untreated, four treated using parastar (40EC 535/10/IN, 20 g/l imidaclopride and 20 g/l lamda-cyhalothrine), and 36 plots treated using 10%, 20% and 30% aqueous leaf extracts separately sprayed against Aphis craccivora (Hemiptera: Aphididae).
Methodology: Four groups of flowers were randomly selected: (1) free, (2) protected from insects, (3) free exclusively to Ap. mellifera and (4) protected against insects.
Results: A total of 10,984 captured flower insects belonged to three orders (Hemiptera, Hymenoptera and Lepidoptera), three families (Aphididae, Apidae and Nymphalidae) and seven species [one (14.3%) sap-sucking Aphis craccivora (Hemiptera: Aphididae), four (57.1%) pollinators Hymenoptera Apidae [Amegilla calens, Amegilla sp., Apis mellifera and Xylocopa olivacea] and two (28.6%) Lepidoptera Nymphalidae [Danaus plexippus and Hypolimnas misippus]. A total of 7,425 insects associated with V. unguiculara corresponded to four orders [Hemiptera (56.7%), Coleoptera (41.5%), Heteroptera and Orthoptera with 0.9% respectively], nine families [Aphididae (45.3%), Chrysomelidae (38.7%), Pyrrhocoridae (4.8%), Coreidae (3.8%), Cicadellidae (2.8%), Coccinellidae (1.9%), Alydidae, Tenebrionidae and Tettigoniidae with 0.9% respectively], 11 genera and 11 species.
Conclusion: Apis mellifera was the major pollinator and Aphis crassivora the major pest. The seed yield was improved by 30% extract of plants without impact on pollinators.
Keywords: Apis mellifera, Leaf Extract, Vigna unguiculata, Calotropis procera, Eucalyptus camaldulensis, Thitonia diversifolia, seed yield, North-Cameroon