Université de Fribourg

Co-formulation of Beauveria bassiana with natural substances to control pollen beetles – Synergy between fungal spores and colza oil

Kaiser, Deborah ; Handschin, Stephan ; Rohr, Rudolf P. ; Bacher, Sven ; Grabenweger, Giselher

In: Biological Control, 2020, vol. 140, p. 104106

Pollen beetles (Brassicogethes spp.) are a major pest in colza (Brassica napus L., also known as oilseed rape) and show increasing resistance to commonly used insecticides. Entomopathogenic fungi (EPF) such as Beauveria bassiana have potential as a sustainable alternative means of control. However, field applications of fungal spores targeting the immigrated beetles on the crop have not been...

Université de Fribourg

Efficiency of natural substances to protect Beauveria bassiana conidia from UV radiation

Kaiser, Deborah ; Bacher, Sven ; Mène‐Saffrané, Laurent ; Grabenweger, Giselher

In: Pest Management Science, 2019, vol. 75, no. 2, p. 556–563

Solar radiation is assumed to be a major factor limiting the efficacy of entomopathogenic fungi used as biocontrol agents in open field applications. We evaluated 12 natural UV‐protective co‐formulants for their effect on the survival of UV‐ exposed Beauveria bassiana spores on agar plates, colza leaf discs and in the field.RESULTS: Colony‐forming unit (CFU) counts of unformulated...

Université de Fribourg

Preventive application of an entomopathogenic fungus in cover crops for wireworm control

Rogge, Sina Alexandra ; Mayerhofer, Johanna ; Enkerli, Jürg ; Bacher, Sven ; Grabenweger, Giselher

In: BioControl, 2017, vol. 62, no. 5, p. 613–623

Efficacy of the Metarhizium brunneum Petch (Hypocreales: Clavicipitaceae) strain ART2825 for control of wireworms (Agriotes obscurus (L.), Coleoptera: Elateridae) was examined in a semi-field pot experiment. Pots were treated in late summer during sowing of spring oat as a cover crop. Survival of wireworms was assessed four weeks after their release in October 2013, and 30 weeks after release in...

Université de Fribourg

A simple in vitro method to study interactions between soil insects, entomopathogenic fungi, and plant extracts

Eckard, Sonja ; Bacher, Sven ; Enkerli, Jürg ; Grabenweger, Giselher

In: Entomologia Experimentalis et Applicata, 2017, vol. 163, no. 3, p. 315–327

A combined application of a biological control agent, such as an entomopathogenic fungus (EPF), with other means of pest control may lead to enhanced or more reliable efficacy of the biocontrol agent. Ideally, the combined components would interact synergistically, yielding significantly higher mortality of the target pest. The mode of such interactions is often unclear and particularly...

Université de Fribourg

Virulence of in vivo and in vitro produced conidia of Metarhizium brunneum strains for control of wireworms

Eckard, Sonja ; Ansari, Minshad A. ; Bacher, Sven ; Butt, Tariq M. ; Enkerli, Jürg ; Grabenweger, Giselher

In: Crop Protection, 2014, vol. 64, p. 137–142

Wireworms are the soil inhabiting larvae of click beetles and can cause severe damage to arable crops such as potatoes (Solanum tuberosum, L.). Several strains of the entomopathogenic fungus Metarhizium brunneum (Petch) are pathogenic to wireworms. In this study, three European strains of M. brunneum were tested in the laboratory against the most damaging wireworm species in Europe, Agriotes...

Université de Fribourg

Temporal and spatial variations in the parasitoid complex of the horse chestnut leafminer during its invasion of Europe

Grabenweger, Giselher ; Kehrli, Patrik ; Zweimüller, Irene ; Augustin, Sylvie ; Avtzis, Nikolaos ; Bacher, Sven ; Freise, Jona ; Girardoz, Sandrine ; Guichard, Sylvain ; Heitland, Werner ; Lethmayer, Christa ; Stolz, Michaela ; Tomov, Rumen ; Volter, Lubomir ; Kenis, Marc

In: Biological Invasions, 2010, vol. 12, no. 8, p. 2797-2813

The enemy release hypothesis posits that the initial success of invasive species depends on the scarcity and poor adaptation of native natural enemies such as predators and parasitoids. As for parasitoids, invading hosts are first attacked at low rates by a species-poor complex of mainly generalist species. Over the years, however, parasitoid richness may increase either because the invading host...