Members of the Genus Beauveria Associated with Natural Populations of Locusts in Southern European Russia

Abstract

The species composition of fungal pathogens among three of the most harmful locust species (Asian migratory locust, Moroccan locust and Italian locust) in the southern Russian Federation was studied. Insects were sampled in 20 locations of seven federal subjects of the Russian Federation (Republic of Dagestan, Republic of Kalmykia; Krasnodar and Stavropol Krai; Astrakhan, Volgograd and Rostov Regions). Forty-five isolates belonging to the fungal genus Beauveria were collected, particularly isolates of B. bassiana and B. pseudobassiana. B. bassiana was the most prevalent, constituting 98% of the samples, and could be differentiated into three clades, as evidenced by the TEF gene and intergenic spacer Bloc. Clade 1, represented by the reference isolate ARSEF 2040, was most abundant (61%), and Clade 2, represented by ARSEF 1811, had lower abundance (27%). The remaining isolates either belonged to the genetically distinct Clade 3, represented by ARSEF 1564, or were found to fall outside the major lineages. The frequency of infection in locust populations was variable and tended to increase under conditions unfavorable for the insects. The vast majority of Beauveria isolates from locusts were highly virulent in this insect group.