Journal of Applied Microbiology, Vol.117, No.5, 1450-1462, 2014
Occurrence of entomopathogenic fungi in tejocote (Crataegus mexicana) orchard soils and their pathogenicity against Rhagoletis pomonella
AimsTo determine the abundance and diversity of entomopathogenic fungi in tejocote orchard soils and evaluate their ability to infect Rhagoletis pomonella Walsh., the main pest of tejocote. Methods and ResultsSurveys were made in two locations in Mexico state and two in Puebla state. Soil from selected locations was baited for entomopathogenic fungi with Galleria mellonella (L.). All isolates were identified morphologically to genus level and to species level using Bloc and elongation factor 1- gene sequence information, respectively; Beauveria bassiana ((Bals.-Criv.) Vuill.), B.pseudobassiana (S.A. Rehner & Humber) and Metarhizium robertsii (J.F. Bisch., Rehner & Humber) were found, with B.bassiana being the most abundant and widely distributed. Pathogenicity of five selected B.bassiana isolates and three M.robertsii isolates was evaluated against larvae and pupae of R.pomonella. All isolates infected larvae resulting in an average mortality of 35%. Pupae were not susceptible; however, adults emerging from inoculated pupae did die due to infection. ConclusionsAt least three species of entomopathogenic fungi are present in the soil from tejocote orchards, with B.bassiana being the most abundant and widely distributed. Rhagoletis pomonella larvae were more susceptible to infection than pupae. Significance and Impact of the StudyOur study has produced new information about the distribution of entomopathogenic fungi in cultivated soils from this region of North America, contributing to a better understanding of their natural occurrence and underpinning the development of biological control approaches.
Keywords:Beauveria bassiana;Beauveria pseudobassiana;Crataegus mexicana;diversity;Metarhizium robertsii;Rhagoletis pomonella;virulence