Antifungal, Antibacterial, Insecticidal and Nematicidal in vitro Activity of Four Plant-based Biopesticides

Abstract

Biopesticides are natural products used in agriculture to reduce the incidence or to eliminate crop pests. They represent an ecological and sustainable alternative to synthetic pesticides, the excessive use of which has serious impacts on human health and the environment. This work evaluates the efficacy of four plant based biopesticides against various plant pests, including insects (Aphidoidea, Zonocerus variegatus, Cosmopolites sordidus), fungi (Aspergillus flavus, Fusarium spp.), bacteria (Pseudomonas spp., Ralstonia solanacearum) and nematodes (Radopholus similis). Laboratory of Phytoprotection and Valorization of Genetic Resources of the Centre for Biotechnology, University of Yaounde 1, between March and June 2025. Four plant based biopesticides (BP1, BP2, BP3 and BP4) were prepared, and their effects were tested in vitro on target organisms. The results of the in vitro tests revealed significant repellent and lethal effects on insects, with repellent and mortality rates reaching over 70% after 48 h of exposure. Similarly, the biopesticides also showed marked antifungal (90-98%), antibacterial (64-93%) and nematicidal (100%) activities, inhibiting the growth of the target organisms and enzymatic synthesis (amylase and cellulase) in the tested fungi. These performances demonstrate that the four plant-based biopesticides (BP1, BP2, BP3 and BP4) possess strong insecticidal, antifungal, antibacterial and nematicidal potential that can be utilized in integrated pest management and sustainable agricultural production programs. Also, they reinforce the interest in biopesticides as sustainable alternatives to chemical pesticides, the use of which is increasingly restricted due to their toxicity to the environment and human health.