Ultrastructure of Tuta absoluta parasitized eggs and the reproductive potential of females after parasitism by Metarhizium anisopliae

Among the microorganisms used in biological control, the muscadine fungus Metarhizium anisopliae (Metsch.) Sorok. is produced and formulated world wide aiming to control pests from several agricultural crops. This work evaluated effects of M. anisopliae isolate UFRPE-6 on the fecundity and mortality of Tuta absoluta (Lepidoptera: Gelechiidae) females and the mechanism of infection on eggs. The infection of the females by the fungus did not affect their oviposition and fecundity; however it affected the survival with total and confirmed mortality of 54.2% and 37.14%, respectively. The eggs were treated with suspension at concentration of 106 conidia/mL. The analysis under scanning electron microscopy showed that conidia germination and penetration processes in the eggs of T. absoluta started within the period of 6 h after the inoculation. Several hyphal bodies were observed from 12 h and an intense extrusion of the mycelium covering all the external surface of the eggs 72 h after inoculation. Despite its moderate activity in adults, the isolate URPE-6 of M. anisopliae showed promising in the control of T. absoluta due to its pathogenicity and virulence to eggs from this pest.