Perspectives of Beauveria bassiana, an entomopathogenic fungus for the control of insect-pests in tea [Camellia sinensis (L.) O. Kuntze]: opportunities and challenges

Injudicious and indiscriminate use of toxic chemicals in tea deteriorates the plant, soil, and environment and escalates maximum residue limits (MRLs) in the end products. This requires for the adoption of safe, eco-friendly and non-chemical sustainable alternatives in tea. Beauveria bassiana is an entomopathogenic fungus that displayed high potential for controlling a wide range of tea pests, including the old looper Biston (= Buzura) suppressaria and the emerging looper Hyposidra talaca, as well as the red spider mite (Oligonychus coffeae) and the tea mosquito bug (Helopeltis theivora). The purpose of this review is to broaden our understanding of B. bassiana-mediated pest control in tea and its action mechanisms in crop protection. This fungal species is known to produce a wide variety of mycotoxins and enzymes in its spores that kill or inhibit the metabolic activity of pests. Numerous environmental and physiological factors, such as moisture, pH, humidity, temperature, atmospheric CO2 concentrations, and fungal spore load (colony forming unit/ml), spore viability, enzyme types in action, host plant chemistry and interactions, insect host species, and insect life stages, can speed up or slow down the microbial-mediated pest interaction in plants. The development of the fungus, sporulation, and multiplication within the host are all influenced by prevailing weather conditions and climate change. Studies on entomopathogen compatibility with tea agrochemicals are critical for optimal field application and adoption of suitable integrated pest management (IPM) schedules. Understanding the physiological, genetic, and molecular perspectives of entomopathogenesis and recent developments to improve mycoinfection could provide novel insights to enhance B. bassiana-mediated pest management in tea. Key steps for quality product formulations and their significance for future sustainability in tea include registering and patenting of biopesticides, mass production, and commercialisation of quality strains.