Specific diversity of the entomopathogenic fungi Beauveria and Metarhizium in Mexican agricultural soils.

Prior knowledge of the local population structure of entomopathogenic fungi is considered an important requisite when developing microbial control strategies against major pests of crops such as white grubs. An extensive survey in the estate of Guanajuato, one of the main agricultural regions of Mexico, was carried out to determine the abundance and diversity of entomopathogenic fungi in soil. Soil collected from 11 locations was baited for entomopathogenic fungi using Galleria mellonella. In addition, all isolates were morphologically identified and selected isolates of Beauveria and Metarhizium isolates identified using Bloc and ITS or Elongation Factor 1-α and ITS sequence information respectively. Genotypic diversity was then studied using microsatellite genotyping. The proportion of isolates belonging to each genus varied amongst all locations. The species Beauveria bassiana, B. pseudobassiana and Metarhizium robertsii were found, with B. bassiana being the most abundant and widely distributed. Microsatellite genotyping showed that the 36 B. bassiana isolates were grouped in 29 unique haplotypes, but with no separation according to geographical origin.