Mangifera indica L. (Sapindales: Anacardiaceae) is a fruit crop that is cultivated in India, China, Thailand, Mexico, Pakistan, the Philippines, Indonesia, Brazil, Nigeria, and Egypt. India is the hub of mango diversity and is also one of the largest producers with an annual production of 18.0 million tons. Though India has the potential for higher production, insect pests act as a stumbling block to obtaining better growth and production of this crop. To date, 400 species of insect pests have been recorded to damage mango [1]. Among them, Amritodus atkinsoni Lethierry (Hemiptera: Cicadellidae) is serious insect pests of this crop [2]. Active nymphal and adult stages can affect the vigor of the trees by sucking the sap [3,4,5]. Several synthetic insecticides have been used to manage such a notorious insect pest [6]. However, continuous and heavy use of insecticides resulted in deleterious complications such as insect resistance, resurgence, and accumulation of soil and fruit residues [7]. These problems can thus be sustainably addressed by developing alternative methods such as biological control agents. In this perspective, screening of the potential entomopathogenic fungus Clonostachys rosea was carried out in this study. This fungus is present in various cultivated and non-cultivated areas, mostly in neutral to alkaline pH soils [8,9,10]. This myco-etiological agent has been classified as pathogenic to fungi, as an endophytic-antagonistic in plants, and as entomopathogenic [9,10,11]. However, only a few studies have characterized the entomopathogenic nature of this fungus. To date, C. rosea infection has been recorded on Oncometopia tucumana Schröder (Hemiptera: Cicadellidae), Sonesimia grossa Signoret (Hemiptera: Cicadellidae), Anopheles stephensi Liston (Diptera: Culicidae), Culex quinquefasciatus Say (Diptera: Culicidae), Hypera postica Gyllenhal (Coleoptera: Curculionidae), Carpomyia vesuviana Costa (Diptera: Tephritidae), Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), and Aphis gossypii Glover (Hemiptera: Aphididae) [10,12,13,14,15]. Additionally, C. rosea is a potential biocontrol agent for several insect pests, pathogenic fungi, and nematode parasites [16].Although some investigations on the entomopathogenic nature of C. rosea have been documented, the nutrition and media optimization for large-scale culturing remain understudied [17,18,19]. The present study is also the first documentation of the entomopathogenic nature of C. rosea against the mango hopper. In addition, its efficacy as a biocontrol agent was assessed by performing an in vitro bioassay on the mango hopper.