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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]

Selected biological control agents and conventional pesticides were used to critically review the applicability of a newly developed Risk Indicator (RI) system. Five basic components are proposed for the calculation of the overall environmental risk score: persistence of the active ingredient, dispersal potential, range of non-target organisms that are affected, and direct and indirect effects on the ecosystem. Several risk measurement systems were reviewed; risk categories in the proposed system were modified from a model developed for classical biocontrol agents. Additionally, one new category was included, to assess the risks to vertebrate non-target species. Besides a detailed discussion of the new RI model, the suitability of the model was demonstrated by calculating the risk scores for 17 selected products. It became obvious that the environmental risk score varied greatly within the assessed chemical products, and also within the group of biological products. The use pattern greatly influenced the estimated environmental risk posed by any given product. The overall environmental risk score varied between a very low risk score of 24 (Coniothyrium minitans, soil application) and a near maximum risk score of 4275 (high risk reference DDT, foliar spray). The proposed model can be used to communicate environmental risk and to design lower risk integrated pest management strategies. It is suggested that the proposed RI system may serve to define low risk and reduced risk pesticides. Yet, it remains debatable whether the RI will be useful in determining acceptability of data waivers for regulatory purposes. [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi are promising alternatives to chemical insecticides. However, a major hurdle concerning the registration of these fungi as plant protection agents is the possible toxicity of secreted metabolites, especially secondary metabolites. This review summarizes data on specific secondary metabolites (destruxins, efrapeptins, oosporein, beauvericin and beauveriolides) produced by the important genera Beauveria, Metarhizium and Tolypocladium. The quantities of secondary metabolites produced by these fungi in vivo are usually much less than those secreted in nutrient rich liquid media. Methods and strategies are suggested which could standardize the risk assessment of fungal biological control agents. [ABSTRACT FROM AUTHOR]

The phytotoxic potential of Beauveria brongniartiiand its main secondary metabolite oosporein were evaluated against seed potatoes (Solanum tuberosum) both in vitroand in situ. In a tray test, potatoes were inoculated using conidiospores and grown either in garden soil or in B. brongniartii-enriched soil. The only significant effect of the treatment was the fact that the weight of the roots was different compared with the controls. The weight of haulm and tubers was unaffected by the treatment with B. brongniartii. No oosporein was detected in the potatoes, although the density of B. brongniartiiin the soil was forty times higher than recommended for the usage of this biological control agent (BCA). This indicates that oosporein does not enter the food chain via potato tubers. The effect of BCA on seed potatoes was also tested in situ. No B. brongniartiiwas detected in the potato field before the application of BCA. Three months after application, an average of 3 × 10[sup 4] colony forming units per gram soil (dry weight) were recorded. Although Melolontha melolonthalarvae damaged 60% of the potatoes, only 3% of the tissue samples were infected with B. brongniartii. The results obtained in this study suggest that B. brongniartiiand its secondary metabolite oosporein pose no risks to potato plants, tubers, or to their consumers. [ABSTRACT FROM AUTHOR]