Comprehensive review of the microbial approach to Mealybug management

Hemiptera insects, like mealybug (Pseudococcidae family), pose a significant threat to agriculture, as evidenced by their status as a major pest and the existence of over 2,000 described species and 290 genera. Their destructive feeding habits lead to significant reductions in quality and productivity. In attempts to mitigate this problem, farmers often prefer the widespread use of synthetic insecticides. However, this conventional approach carries substantial drawbacks, like threats to human and environmental health, biomagnifications, the depletion of natural enemies, and resistance to target pests. The situation is more aggravated when water-based pesticides and biological control agents are quickly becoming ineffective by their cryptic lifestyle, hydrophobic wax covering, and the presence of gut endosymbionts of mealybugs, which together make their management difficult at best. The presence of symbiotic microbes in the saliva of phloem-sucking hemipterans, including mealybugs, enables these insect pests to defeat host plant defences and detoxify insecticides. Gut endosymbionts, wax-degrading bacteria, and entomopathogenic fungi are other promising eco-friendly agents that can channel to suppress populations of this polyphagous insect pest. Here, we review the analysis of conventional approaches to control mealybug infestations. Further, we explore eco-friendly alternatives and unravel cryptic interactions between mealybugs and associated microbes that would protect crops from the relentless menace of this assertive agricultural insect pest.