Effects of Beauveria bassiana Alone and Combined with Yeast-Fermented Prebiotics on Hypothenemus hampei

The coffee berry borer (CBB) Hypothenemus hampei is the major pest of coffee crops worldwide. The use of prebiotics may help increase the efficiency of Beauveria bassiana biological control by enhancing CBB attractiveness or providing a nutritive substrate that may enable the entomopathogenic fungus to initiate the infection process more rapidly. This study evaluated whether the application of B. bassiana combined with yeast-fermented prebiotics affects the attractiveness, development, and infestation of CBB in arabica coffee. The first experiment evaluated CBB attractiveness to the prebiotics Preb1 and Preb2 used in traps compared to methanol:ethanol in the field. The second experiment evaluated in the laboratory CBB preference for fruits treated with B. bassiana alone and combined with the prebiotics. The third experiment evaluated CBB survival and reproduction in fruits subjected to these treatments in the laboratory. The fourth experiment evaluated treatments application on CBB artificially infested in coffee fruits in the field. As main results, greater numbers of CBB were collected in traps with methanol:ethanol. CBB females preferred fruits treated with B. bassiana , B. bassiana + Preb1, and B. bassiana + Preb2 than control fruits. CBB survival and progeny production were greater in the control than in the other treatments. The prebiotics increased B. bassiana efficiency in reducing CBB infestation to coffee fruits only early after application. Although these results suggest potential for the combined use of B. bassiana and prebiotics as a CBB management strategy, the effect was limited. New prebiotic formulations and application strategies should be explored to enhance efficacy.