Nezara viridula (Linnaeus) (Hemiptera: Pentatomidae), commonly known as the southern green stink bug, poses a significant threat to agricultural productivity due to its destructive feeding nature which leads to substantial reductions in crop quality and yield. The entomopathogenic fungal genus Metarhizium (Hypocreales: Clavicipitaceae) has been known as a promising biological control agent with a wide range of arthropod hosts. Among them, Metarhizium anisopliae has shown potential as an alternative management strategy for controlling pests within crop ecosystems. This study aimed to assess the efficacy of different doses of M. anisopliae AUMC 3262 air-dried conidia (0.5, 2.5, and 5 g) against N. viridula adults and evaluate physiological and structural alternations under laboratory conditions. Results indicated that M. anisopliae AUMC 3262 dry conidia induced significant mortality in N. viridula in a time- and dose-dependent manner. Mortality rates reached 86.65%., 99.98% and 100 % of N. viridula after 5 and 6 days of exposure to 0.5, 2.5 and 5 g of dry conidia, respectively. Also, a significant reduction in the total soluble proteins was observed. Scanning Electron Microscope analysis confirmed deformation in the body structure of N. viridula, highlighting fungal penetration and proliferation within the insect's body. Overall, M. anisopliae AUMC 3262 is a virulent strain for N. viridula, which might qualify this strain to be used as a strong candidate for further investigation as a control agent for N. viridula.