Beyond synergy: Integration of entomopathogenic fungi and botanicals as eco-friendly solutions for sustainable pest management
The widespread use of synthetic pesticides in contemporary pest management has been a double-edged sword, while they initially providing effective control of pest populations, their extensive use has ultimately contributed to the emergence of pesticide-resistant pests, accelerating biodiversity loss and environmental polluting by hazardous chemicals. As a result, the development of sustainable alternatives for pest control, including entomopathogenic fungi (EPF) and botanical-derived insecticidal agents, is emerging. Despite their potential, critical limitations inherent to EPF include a slow rate of action and acute sensitivity to abiotic factors, which necessitate synergistic integration with rapid-action botanicals. This paper aims to review combinatorial strategies, that leverage independent yet complementary modes of action, not only preventing the evolution of resistance but also increasing mortality, yielding significantly lower median lethal concentration (LC50) and median lethal time (LT50) values than those obtained with single agent treatments. The reduced doses required for both components improve their suitability for organic agriculture and integrated pest management (IPM) programmes, where minimising pesticide residues is a priority. This review synthesises the current literature and incorporates meta-analysis to discuss how botanicals enhance EPF performance by interfering with insect cuticular defences, altering cuticular permeability, modulating host behaviour and providing protection against ultraviolet radiation and temperature stress. We identified the key issues and areas for improvement in these integration strategies and proposed future directions focusing on compatibility optimisation, advanced formulations and predictive models for sustainable pest management.