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The southern green stink bug, <i>Nezara viridula</i> (L.) (Heteroptera: Pentatomidae) is the most significant pest of soybean worldwide. The present study was conducted to compare the effectiveness of a Delta native strain NI8 of <i>Beauveria bassiana</i> by contact and direct spray on nymphs (2nd to 5th instar) and adults of <i>N. viridula</i>. Water control and four concentrations of <i>B. bassiana</i> were used to evaluate the survival, mortality, and molting percentage and to estimate median lethal concentration (LC₅₀), median lethal sporulation (LS₅₀), and resistance ratio (RR₅₀). Direct spray at all concentrations observed the greatest reduction in survival on all life stages. Mortality and sporulation were positively correlated by concentration, while molting was highly variable with a significantly lower negative correlation on insects that were directly sprayed. Pathogenicity exhibited reduction as young stages developed and emerged to adult. The LC₅₀ (Contact: 612 spores/mm²; Direct spray: 179 spores/mm²) and LS₅₀ (Contact: 1960 spores/mm² Spray: 3.3 × 10⁶) values showed that adults of <i>N. viridula</i> were highly resistant than any other life stage when exposed to either contact or direct spray. Fourth instar was the most susceptible (LC₅₀: Contact: 18 spores/mm²; Direct spray: 23 spores/mm²) (LS₅₀: Contact: 53 spores/mm²; Direct spray: 26 spores/mm²) followed by second, third, and fifth instars.