Susceptibility of Rhodnius ecuadoriensis (Hemiptera: Reduviidae) of fifth instar nymph to the action of Beauveria bassiana

Abstract

Laboratory bíoassays were performed to determine the susceptibility of 5'h instar nymphs of the insect Rhodnius ecuadoriensis to the entomopathogenic fungi, Beauveria bassiana stock UdeA-13. The insects were bred and kept at the Mycology Laboratory, Biology Department, University of Antioquia. The bioassays consisted of direct contact on an insect with a canvas 100% cotton, impregnated with a solution of 3x10⁵, 1x10⁷ 3x10⁸ conidias/ml of the fungi B. bassiana (UdeA-13). The insects were kept in controlled conditions of temperature (25-26ºC) and relative humidity (70-80%) in darkness. lt was found that survival of insects treated with the fungi was low with the three doses; the LT50 for the doses 3x10⁵, 1x10⁷, 3x10⁸ conidia/ml varied between 5.5, 6 and 7 days respectively. The average time of the apparition of mycelia in the cadavers varied between 7-8 days. The results show that B. bassiana (UdeA-13) could be considered a good element in management programs of vectors of Chagas ' disease to interrupt the transmission cycle.