Pathogenicity of three entomopathogenic fungi on pupae and adults of the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae)

Abstract

The pathogenicity of local isolates of the entomopathogenic fungi (EPF) Beauveria bassiana (Balsamo) Vuillemin, Isaria fumosorosea (Wize) (formerly Paecilomyces fumosoroseus (Wise) Brown & Smith) and Metarhizium anisopliae (Metschnikoff) Sorokin (Ascomycota: Hypocreales) were evaluated under laboratory conditions against pupae and adults of Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) via different routes of exposure. Average mortality of pupae after immersing them into spore suspensions was in general low and ranged from 18.7 to 23.9 % depending on fungal species and dose applied. However, adults obtained from treated pupae appeared to have higher mortality rates compared to control with all fungi and doses tested. Adults’ average mortalities ranged from 41.9 to 88.0 % after exposing them to EPF either by feeding on a mixture of conidial suspension and artificial food or by bodily contact with conidia, depending on fungal species, dose and method of exposure. The proportion of cadavers, pupae or adults, that produced visible signs of mycosis ranged from 40.4 to 73.3 % with the exception of those that were exposed to M. anisopliae. In that case, none of the insects that died after exposure to conidia of M. anisopliae developed visible mycelium on their surface. Moreover, confining treated with untreated adults indicated horizontal conidial transmission in some cases. Our results indicate that EPF might be a promising biological control agent for the Mediterranean fruit fly and could be utilised with different modes of application: soil application against pupae and cover or bait sprays against adults.