Publications by authors named "Giselher Grabenweger"

The Japanese beetle, , is an invasive scarab and listed as quarantine organism in many countries worldwide. Native to Japan, it has invaded North America, the Azores, and recently mainland Europe. Adults are gregarious and cause agricultural and horticultural losses by feeding on leaves, fruits, and flowers of a wide range of crops and ornamental plants.

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Combining different biocontrol agents (BCA) is an approach to increase efficacy and reliability of biological control. If several BCA are applied together, they have to be compatible and ideally work together. We studied the interaction of a previously selected BCA consortium of entomopathogenic pseudomonads (Pseudomonas chlororaphis), nematodes (Steinernema feltiae associated with Xenorhabdus bovienii), and fungi (Metarhizium brunneum).

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  • Entomopathogenic fungi (EPF) can control wireworms, but their effectiveness varies in the field, partly influenced by the insect's nutritional status.
  • This study examined how different diets affected the wireworm Agriotes obscurus and its susceptibility to the fungus Metarhizium brunneum, revealing that while diet impacted wireworm growth, it didn't significantly affect infection rates in the lab.
  • Field experiments showed that wireworm damage varied with cover crop species, being highest in diverse mixes and lowest with clover or radish, indicating that the choice of cover crops can influence wireworm management strategies.
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  • Solar radiation significantly reduces the effectiveness of entomopathogenic fungi like Beauveria bassiana when used in open fields, highlighting the need for protective measures.
  • A study tested 12 natural UV protectants, finding that humic acid provided over 90% protection against harmful UV-B radiation, while also improving spore persistence in field tests.
  • Overall, the use of UV protectants such as humic acid, sesame, and colza oil can enhance the survival and efficacy of B. bassiana spores, making them more viable as biocontrol agents in agricultural settings.
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The release of large quantities of microorganisms to soil for purposes such as pest control or plant growth promotion may affect the indigenous soil microbial communities. In our study, we investigated potential effects of Metarhizium brunneum ART2825 on soil fungi and prokaryota in bulk soil using high-throughput sequencing of ribosomal markers. Different formulations of this strain, and combinations of the fungus with garlic as efficacy-enhancing agent, were tested over 4 months in a pot and a field experiment carried out for biological control of Agriotes spp.

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The new C7N aminocyclitol kirkamide (1) was isolated from leaf nodules of the plant Psychotria kirkii by using a genome-driven (1)H NMR-guided fractionation approach. The structure and absolute configuration were elucidated by HRMS, NMR, and single-crystal X-ray crystallography. An enantioselective total synthesis was developed, which delivered kirkamide (1) on a gram scale in 11 steps and features a Ferrier carbocyclization and a Pd-mediated hydroxymethylation.

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Classical biological control is often advocated as a tool for managing invasive species. However, accurate evaluations of parasitoid species complexes and assessment of host specificity are impeded by the lack of morphological variation. Here, we study the possibility of host races/species within the eulophid wasp Pediobius saulius, a pupal generalist parasitoid that parasitize the highly invasive horse-chestnut leaf-mining moth Cameraria ohridella.

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