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Use of entomopathogenic fungi in biological control against sweetpotato whitefly Bemisia tabaci
ŘEHOŘOVÁ, Markéta
The thesis is analyzing effects of selected species and strains of entomopathogenic fungi on the synchronized population of Bemisia tabaci under optimal and sub-optimal conditions. The following species of fungi were used during the experiments: Aschersonia aleyrodis, Lecanicillium lecanii (former Verticillium lecanii), Isaria fumosorosea (former Paecilomyces fumosoroseus) a Beauveria bassiana. There was a experiment of mortality of all these fungi in the frequency of 7, 14, and 21 days, while all these experiments were made under the same conditions (concerning temperature and humidity) in order to keep all the results comparable. In the case of Isaria fumosorosea, the experiment was taken also under sub-optimal conditions in order to compare effectiveness of this significant fungi, both under the optimal conditions (relative air humidity 95-100 %, temperature 25{$\pm$}1°C), and sub-optimal conditons (relative air humidity bellow 75 %, temperature 25{$\pm$}1°C). Greater attention was also given to A. aleyrodis which represents one of the most important fungi on the field of whitefly combat.
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Use of macroorganisms and microorganisms in biological control of whiteflies
ŽÁKOVÁ, Erika
Whitefly is one of the most important greenhouse pests that can cause significant damage to crops. Whitefly suck juice from plants and produce honeydew which is sugar source for saprotrophic fungi called sooty mold. Fungi cover the leaves and reduce the leaf assimilation area. The most serious harm of whiteflies is attributed to transfer of many plant viruses. The most serious whiteflies commonly found in the greenhouses are Trialeurodes vaporariorum and Bemisia tabaci. For the control of whitefly populations, the seasonal inoculum strategy of biological control is used, with the aim of immediately overlapping the pest with the right choice of natural enemies. Biological control contributes to the control of whiteflies in the greenhouse, specifically the use of natural enemies based on macro-organisms and microorganisms. The macroorganisms include parasitoids and predators. The most important commercially used whitefly parasitoids are Encarsia formosa, Eretmocerus eremicus and E. mundus. Predators used in biological control against whitely is the predatory bug Macrolophus caliginosus, the predatory ladybug Delphastus catalinae and the predatory mite Amlyseius swirskii. Parasitic wasps are narrowly specialized in both whitefly species, while predators are polyphagous species that can feed on more pest species. Bioproducts based on entomopathogenic fungi are also used against whiteflies in the abroad. The most important species are Aschersonia aleyrodis, Isaria fumosorosea, Beauveria bassiana and Lecanicillim muscarium. For the effective use of these bioagents, it is important to have knowledges not only about pest, but also about interaction among pest - natural enemy - host plant. So it is important to perform quality monitoring of whiteflies in the greenhouse to make the use of natural enemies profitable.
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