Association of Heterorhabditis amazonensis and Beauveria bassiana aiming the control of Hypothenemus hampei

Abstract

Among the main problems for coffee production, it is possible to mention the occurrence of coffee borer, Hypothenemus hampei. In order to seek alternatives to control the pest, the proposed objective was to evaluate the interaction between Beauveria bassiana UFU01 and Heterorhabditis amazonensis MC01 on the control of coffee borer. Therefore, four experiments were set. In the first, B. bassiana UFU01, H. amazonensis MC01 and both entomopathogens associated were applied in bored fruits displaced in vermiculite. In the second experiment, the methodology was similar to the previous one; however, the fruits were immersed in the suspensions. In the third experiment was evaluated the transport of B. bassiana UFU01 conidia by H. amazonensis, checking the mortality of Tenebrio molitor. In the fourth experiment, the fungus and the nematode were added to Petri dishes containing agar-water simultaneously to observe if the nematodes could carry B. bassiana UFU01 conidia. The obtained data were subjected to analysis of variance and the Tukey test (p <0.05), for comparison between means and regression analysis. It was found that, when entomopathogens were applied to vermiculite, treatments using B. bassiana UFU01 and H. amazonensis alone caused the highest mortality of H. hampei adults. For larvae, there was no difference among treatments. The same was observed when the fruits were dipped in the suspensions, with no difference among treatments. As for T. molitor mortality, it was observed that there was no difference among treatments. However, when applied in combination, there was a higher mortality caused by B. bassiana compared to H. amazonensis. In the last experiment, juveniles and conidia were found on the opposite side of the dish, and it can be inferred that the presence of conidia was due to transport by infective juveniles.