Virulence of Beauveria bassiana (Deuteromycetes) Strains Against the Coffee Berry Borer (Coleoptera: Scolytidae)

Abstract

The virulence of 9 strains of the fungus Beauveria bassiana (Balsamo) Vuillemin against the coffee berry borer, Hypothenemus hampei (Ferrari), was determined under laboratory conditions. Results show that B. bassiana is a potential microbial agent suitable for incorporation into a program of integrated control directed against H. hampei. The 3 most aggressive strains were Bb-4 (Ecuador), Bb-25 (Mexico), and Bb-26 (Mexico) with LC50s of 0.003,0.004, and 0.006%, respectively, which are equivalent to 2.2 X 106, 4.1 X 106, and 5.9 X 106 conidia per milliliter of suspension. Mean lethal times (TL50) were between 4.3 and 7.5 d. The maximum percentage of cadavers that sporulated was obtained with strain Bb-25 at 90%, with 81.9% registered for Bb-17 and 81.9% for Bb-26. The lowest percentage of sporulation was observed for Bb-14 at 62%.