Comparative Effect of Synthetic Insecticide and Botanical Extracts on the Abundance of Pollinators in Okra Agrosystem in Boklé, North Cameroon

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.