Evaluation of Native Entomopathogenic Fungi Isolates for Microbial Control of the Mediterranean Fruit Fly (Ceratitis Capitata (Diptera: Tephritidae)) Pupae and Adults

Abstract

Two isolates of the entomopathogenic fungi (EPF) Beauveria bassiana (Hypocreales: Cordycipitaceae), an isolate of Aspergillus flavus (Eurotiales: Trichocomaceae), of Verticillium sp. (Glomerellales: Plectosphaerellaceae) and of Aschersonia sp. (Hypocreales: Clavicipitaceae) were evaluated for their pathogenicity against the Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae) pupae and adults under laboratory conditions, using four different concentrations. Pathogenicity towards pupae and adults was tested via spraying and body contact bioassays respectively. Average mortality of treated individuals ranged from 60 to 100% for pupae and from 39 to 100% for adults depending on the fungal isolates and concentrations. The highest mortality levels were observed for individuals treated by Verticillium sp., A. flavus and Aschersonia sp., while the B. bassiana isolates were the less effective against both adult and pupae. Estimated lethal concentrations 90 ranged from 3x105 to 3.8 x 107 conidia/ml for adults and from 6.58 x 103 to 2.5 x 105 conidia/ml for pupae with lower values calculated for A. flavus, Verticillium sp. and Aschersonia sp. Mean lethal times 90 were less than 79h for C. capitata adults and ranged from 94 to 273 hours for pupae according to the fungal isolates. Microscopic observation of treated pupae showed a mycelium growth on the bodies of death individuals, while visible signs of mycosis are less observed for adults. Results of these experiments demonstrated that native EPF isolates could be a promising biocontrol agent to manage safely C. capitata and might be used against pupae by soil application or against adults by cover or bait sprays.