Effect of Entomopathogenic and Nematofagous Fungi on the behaviour of the Black Banana Weevil (Cosmopolites sordidus, Germar, 1824) (Coleoptera Curculionidae): Biological Control

The present work has led to the detection of VOCs of fungal origin that acts as repellents against Cosmopolites sordidus (BW), pest-key of the banana tree (Musa spp.). Initially, the identification of the VOCs produced by two different Beauveria bassiana strains (Bb203 and Bb1TS11), a Metarhizium anisopliae strain (Ma4TS04) and a Pochonia clamydosporia strain (Pc123), was made through the use of GC/MS-SPME (Gas Chromatography/Mass Spectrometry - Solid-Phase Micro Extraction). The GC/MS- SPME analysis led to the identification of 193 different VOCs, among which 5 repellent candidates were identified. The selected VOCs, together with two repellent compounds of Rhynchophorus ferrugineus (C1 and C2) and two technical repellents (garlic and colloidal sulphur), were tested in vitro to evaluate their effect on the behaviour of C. sordidus, in laboratory conditions. Of the repellent candidates tested, only two (C1 and C2) were used for in vivo tests. From the findings of in vitro data, hard-repellents (C7 and C5) can be considered effective repellents in the management of C. sordidus. Soft-repellents (C1, C2, C3, C4, C6 and garlic) are considered repellent, although milder, for BW under laboratory conditions. Infield tests, however, both tested VOCs did not exhibit the same repellent action shown in the laboratory. This phenomenon could be ascribed more to the more complex environmental conditions of in vivo tests than to those in vitro, but also the non-optimal VOCs dispersion technology used for field tests. Therefore, in vitro, new VOCs have been identified that can be used as repellents for BW. The implementation of technologies associated with the dispersion of these repellents could produce progress in the agrobiotechnological sustainability of world banana cultivation