Abstract: The fungal biocontrol agent GranMet-GRTM containing Metarhizium brunneum BIPESCO 5 is used against larvae of the maize pest Diabrotica virgifera virgifera. The product was used for a preventive application in maize fields in Styria (Dietzen, Laafeld) and Tyrol (Oberndorf, St. Johann in Tirol, Austria). Until the end of the planting season 2016 the Metarhizium spp. abundance was significantly raised in three of four treatment sites (field size: 2 to 12 ha). With a SSR-PCR based molecular technique the applied strain BIPESCO 5 could be identified out of 14 different genotypes isolated from all soil samples (n = 192). In Styria fewer emerging Diabrotica adult beetles were caught compared to the previous years. No damage of maize plants was detected in Laafeld, less than 10% lodging was assessed in the treated field in Dietzen. In the untreated control field more than 80% lodging occurred with a yield reduction of more than 30% (- 4.2 t/ha). In Tyrol no emerging beetles got trapped but a high number of D. v. virgifera was assessed on PAL sticky traps for the first time x = 259.83 beetles per trap; n = 6).