Mass application of the insect pathogenic fungus Metarhizium brunneum BIPESCO 5 can be used for biological control of corn rootworm(Diabrotica v. virgifera). Long-term field trials were conducted in three Austrian maize fields with different cultivation techniques and infestation rates to evaluate the efficacy of the treatment in controlling the pest larvae. In addition, the structure of native Metarhizium spp. populations was studied to compare the different field sites with BIPESCO 5 mass application.
Annual application of the product Granmet-PTM (barley grains colonized by Metarhizium ) increased the density of Metarhizium spp. in the treated soil. Although a decrease in pest population was not achieved in heavily infested areas, less damage occurred in treated areas compared to control areas. Metarhizium population structure differed significantly among treated field sites. Results indicated that despite intensive applications, native populations of Metarhizium spp. can coexist in these habitats, but that mass applications should be repeated regularly. To date, crop rotation has been the method of choice for corn rootworm control in Europe, but application of M. brunneum may provide an additional means of control.
Authors: Maria Zottele, Johanna Mayerhofer, Hannah Embleton, Katharina Wechselberger, Jürg Enkerli and Hermann Strasser