Evaluation of the entomopathogenic fungusBeauveria bassiana strain ATCC 74040for the management of Ceratitis capitata

摘要

The effectiveness of the bioinsecticide Naturalis based on the Beauveria bassiana (Balsamo) Vuillemin (Deuteromycotina Hy-phomycetes) strain ATCC 74040 against the medfly Ceratitis capitata (Wiedemann) (Diptera Tephritidae) was evaluated in labo-ratory and field experiments. Under laboratory conditions, the bioinsecticide (150 m1/1) protected fruits from medfly ovipositionsmore effectively when they were covered uniformly with a spray volume of 5.4 ml/fruit. In laboratory choice bioassays medflyfemales laid respectively 5 and 3 times more eggs on untreated fruits and on fruits sprayed with inert co-formulants of the bioin-secticide than on fruits treated with the bioinsecticide. However, females did not prefer to oviposit on untreated fruits over fruitssprayed with co-formulants, suggesting that inert co-formulants did not affect oviposition behaviour of C. capitata females.Adults landed indifferently on both untreated fruits and fruits sprayed with the bioinsecticide and medflies did not appear to berepelled by chemical compounds or fungal structures of B. bassiana. However, in no-choice laboratory tests significantly morepunctures per fruit were observed on untreated fruits than on fruits treated with the bioinsecticide, suggesting that medfly femalesprefer untreated over treated fruits to effectively oviposit. Preliminary field trials were conducted to confirm the effectiveness ofthe B. bassiana-based bioinsecticide for medfly control. The bioinsecticide was as effective as a pyrethroid in reducing adult med-fly populations and protecting orange fruits in the field. However, our results suggest that the bioinsecticide could be a valuableadditional tool for the management of C. capitata in both integrated and organic groves.