Effects of Beauveria bassiana on the growth and reproductive rates of Nezara viridula

A laboratory colony of the southern green stink bug, Nezara viridula L. (Heteroptera: Pentatomidae) was used to evaluate the effect of two strains of Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Cordycipitaceae) on its growth and reproductive rates. Four concentrations (106, 107, 108, and 109 conidia g−1) of native (NI8) and commercial (GHA) entomopathogenic fungi alongside a water control were used. Cumulative oviposition and survival of nine groups (ten couple per group per concentration) were used to calculate the demographic parameters of this insect. Two computations were done based on total offspring (fertile and infertile eggs) and eggs with developed embryo (fertile eggs). Net reproductive rates (Ro) on insect sprayed with NI8 calculated based on total offspring showed a dose-dependent effect (72.55, 85.50, 58.15, and 37.60 females per newborn female) compared with water control (87.65). In populations sprayed with GHA, only the highest concentration (109 conidia g−1) was lower than control (27.15). The calculated Ro values based on fertile eggs were much lower as it was expected with 60.75, 61.45, 45.45, and 32.05 females per newborn female from lowest to highest concentrations of NI8 and 21.50 for GHA highest concentration compared with water control (78.45). These results demonstrated that both native and commercial strains affected embryo development, decreasing growth and reproductive rates of N. viridula populations. Further field testing is needed to evaluate the potential for in-field control.