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Entomopathogenic fungi are used for biological control of insect pests. Metarhizium brunneum Petch (Hypocreales) has potential to control Diabrotica virgifera virgifera LeConte (Chrysomelidae), which is a major pest of maize in North America and has recently invaded Europe. The inundative application of an entomopathogenic fungal strain in biological control results in high densities of fungal propagules in the soil which can potentially affect soil microbial communities and their multiple functions in soil. The objective of the present study was to assess potential effects of M. brunneum on soil fungal and prokaryotic communities in a pot experiment over a time course of 4 months using high-throughput sequencing (HTS) of ribosomal markers. The application of M. brunneum formulated as fungus colonised barley kernels (FCBK) led to a significant increase of the applied strain in soil, as assessed by cultivation-dependent (plating on selective medium followed by genotyping of Metarhizium isolates) and cultivation-independent (HTS of ribosomal markers) approaches. Data revealed that soil fungal and prokaryotic community structures did not change after the application of M. brunneum. Temporal changes of the fungal and prokaryotic communities were observed and the prokaryotic communities showed minor changes to barley kernels (BK), the matrix of the formulation. Results of this study are in accordance with other investigations lacking any evidence for adverse effects on microbial communities caused by applied entomopathogenic fungi. [ABSTRACT FROM AUTHOR]

The effect of increased duration of seed treatment with two fungal entomopathogens, Beauveria bassiana (NATURALIS) and Metarhizium brunneum (BIPESCO5), on the growth and colonization of broad bean ( Vicia faba ) was assessed in two replicate greenhouse experiments. The plants were inoculated by soaking seeds in a concentration of 1 × 10 7 conidia ml −1 of each of the two fungal strains or in sterile distilled water containing 0.1% Tween 80 for 2, 8, and 16 h. Percent seed germination and seedling emergence as well as primary root length were determined seven days post inoculation. Effects of fungal strain and seed treatment duration on plant height, number of leaf pair, fresh root and shoot weight were measured 14 and 28 days post inoculation. Seed treatment with either fungal strain significantly enhanced almost all measured plant growth parameters. Overall, plant growth was also significantly enhanced as seed treatment duration increased; irrespective of fungal strain. Percent colonization of different plant parts (root, leaf, and stem) sampled 14 and 28 days post inoculation increased as the duration of seed treatment increased as well. The increase in colonization rate due to increased seed treatment duration varied significantly among plant parts, but not among both sampling dates. Our study demonstrates that M. brunneum can systemically colonize different plant parts and improve plant growth when applied as a seed treatment. This was also confirmed for the well-known endophytic B. bassiana strain used in this study. Our results also provide the first report for the effect of increased duration of seed treatment with both endophytic fungal entomopathogens on plant growth enhancement. [ABSTRACT FROM AUTHOR]