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The parasitoid community of two microlepidopteran species living on hops
Hovorka, Tomáš ; Janšta, Petr (advisor) ; Libra, Martin (referee)
Interactions between parasitoids, phytophagous insects and their host plants play one of the crucial role in the trophic relationships of terrestrial food webs. According to current knowledge, more than half of all known terrestrial species are part of this food web (parasitoids- herbivores-plants). In many species of herbivore hosts, interactions with parasitoids have led to the evolution and diversification of different defense strategies. An example of a primary defense strategy against predators and parasitoids is the formation of shelters such as leaf mines, leaf cocoons or galls. These strategies are a key factor influencing the composition of the parasitoid community. In this thesis, the complex of parasitoids in two microlepidopteran species with different life strategies living on hops (Humulus lupulus) was investigated. The caterpillars of Caloptilia fidella (Lepidoptera: Gracillaridae) first mine within leaves of hops, later, when they start to feed exophagously, they create leaf rolls and cocoons on the outer surface of the leaf. Caterpillars of the species Cosmopterix zieglerella (Lepidoptera: Cosmopterigidae) remain in the mine throughout their larval development. The obtained parasitoids were identified both based on morphology and with the help of two gene fragments, namely CO1 and...
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Natural enemies of the European spruce bark beetle \kur{Ips typographus}
BÁRTA, Jiří
Bark beetles (Scolitynae) are among the most important pests of forest stands, where they cause extensive damage, especially in spruce monocultures. Their negative effect is to attack the host tree, which is its source of food and at the same time provides them with space for reproduction. The bark beetle is able to have several generations per year under suitable temperature conditions. One of the most widespread is consi-dered to be the European spruce bark beetle Ips typographus. This species is able to search for weakened and abiotically damaged trees. Integrated Pest Management of forests includes several effective methods against bark beetles. The most used met-hods include the installation of feromone traps, traps trees and poisoned tripods. The European spruce bark beetle is in their population regulated by many natural enemies. From parasitoids such as Coeloides bostrichorum and Rhopalicus tutela and predators Thanasimus formicarius and Medetera spp. to pathogenic microorganisms such as entomopathogenic viruses, bacteria, protozoa, microsporidia and especially entomo-pathogenic fungi belonging to the order Hypocreales. The most important species is the fungus Beauveria bassiana, which has the greatest potential in the biological pro-tection of spruce stands.
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Use of macroorganisms and microorganisms in biological control of aphids
BOŠKA, David
Aphids are one of the most important species of pests, occurring on all continents except Antarctica. Aphids are harmful mainly by sucking, honeydew production and transmitting hundreds of viral diseases. The most important greenhouse aphids occurring in the Czech Republic are the green peach aphid (Myzus persicae) and the cotton aphid (Aphis gossypii). Their danger lies in the rapid development cycle, when there is a rapid increase in populations. Despite the great damage they cause, aphids are very defenceless and small insect with a large number of naturally occurring enemies. The most important natural enemies are predators, parasitoids and entomopathogenic fungi. In the biological control of plants against aphids, the predator ladybeetles (Coccinellidae), lacewings (Chrysopidae) and the aphidophagous gall midge (Aphidoletes aphidimyza) are mainly used. In the nature, aphids are also regulated by hoverflies (Syrphidae). The most important aphid parasitoids are mainly the parasitic wasps Aphidius colemani, Aphidius ervi and Aphelinus abdominalis. From the microorganisms, the polyphagous entomopathogenic fungi are used, they cause primary infections in several species of pests. From the microorganisms, entomopathogenic fungi are mainly entomopathogenic fungi that can attack polyphagous more species of harmful organisms. The bioproducts based on entomopathogenic fungi Lecanicillium lecanii, Beauveria bassiana and Isaria fumosorosea are available on the foreign market. They were developed for biological control against aphids and other pests.
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