Comparative Effect of Synthetic Insecticide and Botanical Extracts on the Abundance of Pollinators in Okra Agrosystem in Boklé, North Cameroon
Youssoufa Ousmana
Zoology unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, Douala, Cameroon.
Charlotte Sah
Zoology unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, Douala, Cameroon.
Taïmanga
National Higher School of Agronomy, Fisheries and Veterinary Medicine (ENSAHV), University of Douala, Douala, Cameroon.
Moukhtar Mohammadou
Faculty of Science, Department of Living Organisms, Biological Sciences, University of Garoua, Garoua, Cameroon.
Moïse Adamou
Laboratory of Parasitology and Applied Entomology, Department of Biological Sciences, Faculty of Sciences, University of Ngaoundere, Ngaoundere, Cameroon.
Sedric Junior Tsekane
Zoology unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, Douala, Cameroon.
Andrea Sarah Kenne Toukem
Zoology unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, Douala, Cameroon.
Auguste Pharaon Mbianda
Botany Unit, Laboratory of the Biology and Physiology of Plant Organisms, University of Douala, Douala, Cameroon.
Edith Laure Kenne
Zoology unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, Douala, Cameroon.
Abraham Tchoubou-Sale
National Higher School of Agronomy, Fisheries and Veterinary Medicine (ENSAHV), University of Douala, Douala, Cameroon.
Nadine Esther Otiobo Atibita
Zoology unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, Douala, Cameroon.
Martin Kenne
*
Zoology unit, Laboratory of the Biology and Physiology of Animal Organisms, University of Douala, Douala, Cameroon.
*Author to whom correspondence should be addressed.
Abstract
Background: Pollinator-dependent crops such as okra face increasing threats from intensive pesticide use, creating a need for eco-friendly pest management solutions that effectively control pests while preserving pollinator diversity and activity.
Aims: Synthetic pesticides pose severe threats to non-target beneficial insects, necessitating eco-friendly alternatives for sustainable agriculture.
Study Design: Ecological survey was conducted in 11 trials (four plots each).
Place and Duration of Study: Investigations were carried out in Garoua (Bocklé) from June 15 to October 10, 2022.
Methods: The study evaluated the comparative impact of a synthetic insecticide (TEMA) and aqueous leaf extracts from three local plants (Azadirachta indica, Eucalyptus camaldulensis and Senna occidentalis) at 5%, 10%, and 15% doses on six pollinators in okra plots across six consecutive days. Data were analysed using the negative binomial generalized linear models (GLM-NB) and the robust permutation ANOVA (5,000 iterations).
Results: Out of 991 specimens, Apis mellifera adansonii acted as a keystone species, representing 53.5% of the total pollinators. TEMA triggered an immediate, devastating (90.0%) collapse in pollinators on day 49. Botanical extracts safely sheltered 85.5% pollinators. Permutation procedure unmasked significant triple interactions (P = .011). High-dose extracts (15%) exerted no repellent or toxic effect on Amegilla calens, Megachile cincta, butterflies or hoverflies, optimising and stabilising pollinator residency curves late into the cycle.
Conclusion: High-dose extracts offered excellent ecotoxicological safety and non-selective bio-prevention, providing an ecologically sound alternative to conserve biodiversity in sustainable agrosystems.
Keywords: Botanical biopesticides, ecotoxicological safety, permutation ANOVA, Apis mellifera adansonii, Abelmoschus esculentus, wild solitary bees, agroecology