Resumen

CAZORLA PERFETTI, Dalmiro José; MORALES MORENO, Pedro  y  ACOSTA QUINTERO, María Eugenia. Effects of Thermal, Saline and pH Gradients on in vitro Germination of a Native Isolate of Beauveria bassiana (Bálsamo) Vuillemin, Pathogenic to Rhodnius prolixus and Triatoma maculata. Rev. Cient. (Maracaibo) [online]. 2007, vol.17, n.6, pp.627-631. ISSN 0798-2259.

Beauveria bassiana (Bàlsamo) Vuillemin is an entomopathogenic fungus widely used as a microbial control agent in many countries. As an attempt to determine the influence of environmental factors on germinative process, the in vitro effects on Lactrimel-agar medium of thermal (6 to 40°C), saline (4 to 70%NaCl) and pH (1.32 to 12) gradients on conidial germination of a native isolate (LF14) of B. bassiana, highly virulent to Rhodnius prolixus y Triatoma maculata, vectors of American tripanosomiasis in Venezuela, were studied. Conidios were not able to germinate at extreme temperatures (6 and 40°C), whereas the germination rates were high at thermal range of 21-34°C. Germination rates decreased significantly with increases of NaCl concentration ([NaCl]) and the germinative process was fully inhibited over a range of [NaCl] 7% and at pH 1.32 and 11-12. Germination rates were significantly higher (99%) at pH range of 4 to 10. In spite of the influence of further abiotic and biotic factors need to be determined, the native isolate LF14 of B. bassiana showed a high in vitro level of tolerance for a wide range of environmental stressant factors (temperature, pH, [NaCl]). Thus, this fungal isolate appeared to be considered as a potential biocontrol agent to be used in integrated control strategies against triatomine vectors.

Palabras clave : Beauveria bassiana; conidial germination; temperature; salinity; pH.