Jehle, Johannes A.

Leclerque, Andreas

Philippi, Jasmin

Saar, Katharina

Schliephake, Edgar

Stephan, Dietrich

Werner, Manuel

English

JKI Open Journal Systems (Julius Kühn-Institut)

Nachwuchswissenschaftlerforum / Young Scientists Meeting 2015 Saar et al.   Determination of the potential of the entomopathogenic fungi Isaria fumosorosea as a BCA against pest insects  Katharina Saar1, Jasmin Philippi2, Edgar Schliephake2, Andreas Leclerque3, Manuel Werner1, Johannes A. Jehle1, Dietrich Stephan1 1 Institute for Biological Control, Julius Kühn Institute, Darmstadt 2 Institute for Resistance Research and Stress Tolerance; Julius Kühn Institute, Quedlinburg 3 Institute for Microbiology and Biochemistry, Geisenheim University, Geisenheim Email of corresponding author: katharina.saar@jki.bund.de   Entomopathogenic fungi like Isaria sp., Metarhizium sp. and Beauveria sp. are important biological control agents due to their lethal effects against several insect pests. The aim of the EU-funded project BIOCOMES is therefore the use of the natural ubiquitous entomo-pathogenic fungus Isaria fumosorosea (Ascomycota: Hypocreales: Cordy-cipitaceae) in an integrated pest man-agement strategy to control pest in-sects in greenhouses. The selection of highly virulent and ef-fective strains is one of the necessary prerequisites. Therefore, several strains of Isaria sp., obtained from different geographical origins and hosts, were compared for their efficacy and viru-lence against various pest insect species from the orders Lepidoptera and Hemiptera. By means of various patho-genicity assays, the efficacy and median lethal concentration (LC50) of different Isaria strains against Spodoptora exigua (beet armyworm) and Bemisia tabaci (whitefly) were investigated. Depending on the Isaria strain, the mortality rates differed from 30 % to 76 %. The feeding of whiteflies on plants may cause direct damage to the leaves as well as virus transmission by their sucking behaviour. In addition to the mortality effects, insects showed changes within their behaviour when they were infected with I. fumosorosea. In order to evaluate whether adults of B. tabaci, which had been infected and non-infected with Isaria, showed differences in their feeding (sucking) behaviour, the electrical penetration graph method (EPG) was used to observe behavioural changes, e.g. penetration frequencies. First results of the comparisons concerning the changes within the waveform and durations will be shown.  Presently, different molecular methods like RFLP are used for the characteriza-tion of virulence factors and differences between the strains of I. fumosorosea from different geographical origins and hosts and its influence on different ac-tivity patterns as mentioned above.    20 Berichte aus dem Julius Kühn-Institut 181

Determination of the potential of the entomopathogenic fungi Isaria fumosorosea as a BCA against pest insects

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Determination of the potential of the entomopathogenic fungi Isaria fumosorosea as a BCA against pest insects

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