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Possibilities of use of selected entomopathogenic fungi in biological control of agricultural pest species
KONOPICKÁ, Jana
Ph.D. thesis is focused on the entomopathogenic fungi that can be used in biological control. Ph.D. thesis consists of two main parts: 1) a detailed background research, and 2) five subchapters of the experimental part and results, which contain original publications describing results of my own studies. The first study focused on the isolation and identification of new strains of entomopathogenic fungi from soil samples collected in garlic and onion fields in the Czech Republic and Israel. Furthermore, the efficacy of selected fungal strains against the bulb mite Rhizoglyphus robini was tested. A total of 5 genera of entomopathogenic fungi (Metarhizium sp., Beauveria sp., Isaria sp., Lecanicilium sp. and Purpureocillium sp.) were identified among the soil isolates from both countries. The most frequent was the genus Metarhizium sp. especially in sampling sites of the Czech Republic. The highest efficacy against Rhizoglyphus robini mites was found in Metarhizium anisopliae strains isolated from soil samples collected in the Czech Republic and in Metarhizium indigoticum strain from Israel. Mortality after 4 days of the bioassay was almost 100%. The second study investigated the efficacy of the entomopathogenic fungus Isaria fumosorosea CCM 8367 against box tree moth (Cydalima perspectalis). Fungal infection was mostly observed in pupae. However, mortality did not exceed 60%, indicating a very low susceptibility of box tree moth to Isaria fumosorosea CCM 8367. In the third subchapter, various strains of entomopathogenic fungus Beauveria bassiana were tested against the Colorado potato beetle, a serious pest of potato. First, laboratory experiments were performed and the most virulent strain BBA 08 against this pest was selected and used subsequently in further experiments. The strain efficacy against L. decemlineata adults was evaluated in pot experiments and under field conditions. The fungus was applied alone and in combination with entomopathogenic nematodes. In all experiments, the fungus reduced the number of Colorado potato beetle adults by about 30% compared to the control. The fourth study described enrichment of soil substrate with entomopathogenic fungus Isaria fumosorosea CCM 8367 for increasing its suppressivity. The results showed that the fungus successfully colonized the soil substrate and remained in it for more than 6 months at 20 °C, although the average concentration decreased slightly from 5.89×104 to 2.76×104 spores per milliliter of substrate during the experiment. The last study described dissemination of Isaria fumosorosea CCM 8367 spores by nematodes of Steinernema feltiae and Heterorhabditis bacteriophora. The results of our study revealed for the first time that the spread of conidia and blastospores of Isaria fumosorosea in soil environment is significantly enhanced by the presence of entomopathogenic nematodes.
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Efficacy of entomopathogenic fungus \kur{Metarhizium anisopliae} against different hosts
KONOPICKÁ, Jana
Entomopathogenic fungus \kur{Metarhizium anisopliae} is one of the most common species used in biological control against pests. The thesis is analyzing effectiveness of original strains and continuously passaged strains of \kur{M. anisopliae} through nutrient substrates and different developmental stages mealworm \kur{(Tenebrio molitor)}. For original and continuously passaged strains were also evaluated the growth and spore production at different temperatures cultivation. In this thesis was investigated the efficacy of the original strains of \kur{M. anisopliae} on selected economically important pests. Strains were tested on populations of adults Pollen beetles \kur{(Meligethes aeneus)} and Cabbage seedpod weevil \kur{(Ceutorhynchus obstrictus)} and the eggs of Colorado potato beetle \kur{(Leptinotarsa decemlineata)} in laboratory conditions. Other entomopathogenic fungi were tested on the eggs of Colorado potato beetle eggs.
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Entomopathogenic fungus \kur{Metarhizium anisopliae} - biological characterization
KONOPICKÁ, Jana
Entomopathogenic fungus \kur{Metarhizium anisopliae} is one of the most common species used in biological control. Fungus \kur{M. anisopliae} occurs in humid and warm environments. Fungus is able to cause the primary diseases of insect living in soil or on the soil surface. The fungus is widely polyphagous and parasites on a wide range of insects belong to more than 50 orders (Orthoptera, Diptera, Hemiptera, Lepidoptera and Coleoptera). The bachelor´s thesis is focused on a detailed description of the fungus \kur{M. anisopliae} and also characteristic of the other six major genera of fungi used in biological control (\kur{Beauveria, Hirsutella, Isaria, Nomuraea, Paecilomyces, Lecanicillium}) including description of development cycle of entomopathogenic fungi. The thesis also contains a detailed description of the four commercially available biological products based on this fungus \kur{M. anisopliae} (Met52, Green Muscle?, BioCane and BIO-Blast) and examples of practical use of biopreparate Met52 on the selected host.
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