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Determination of volatile isoprenoids as water stress markers of spruce resistance against bark beetle
Slušná, Michaela ; Kalinová, Blanka (advisor) ; Hoškovec, Michal (referee)
Isoprenoids are important components of conifer resin and represent an important part of constituted defence system against herbivores and pathogens. Drought is one of the most important factors that influences the tree physiology and resitance. Due to decreased turgor of resin canal cells, the water insufficiency affects the pressure of the resin and thereby the ability of trees to physically prevent pathogen or herbivore invasion by effective outpouring of the resin. In addition, drought can also change the resin composition and thus can influence the quality of volatiles emitted by the tree. The Norway spruce, Picea abies, is the predominant species of production forests in moderate climate zone. Bark beetles, Ips typographus, represent the most important pest species of spruce. In general, pioneer bark beetles use host volatiles to orient themselves toward the tree suitable for colonization and in many species host volatiles synergize bark beetle aggregation pheromones. Thus the host volatile composition could affect significantly host colonization. This diploma thesis studied the influence of drought on the production and composition of isoprenoid volatile organic compounds in 80 - 100 years old spruce trees. Using I. typographus antennae as biological detectors, we also studied which resin...
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Factors affecting efficacy of pheromone lures for spruce bark-beetles
Zahradníková, Marie ; Holuša, Jaroslav (advisor) ; Emanuel, Emanuel (referee)
This thesis evaluates the effectiveness of defensive techniques against the spruce bark beetle (Ips typographus L.) with a primary focus on pheromone traps and selected factors affecting their efficacy. The factors tested are the setup system of pheromone traps and type of pheromone dispenser baits, the effect on the efficacy of pheromone traps of increasing evaporated pheromones, a comparison of the biological efficacy of different types of pheromone dispensers and an assessment of their impact on the swarming curve. In addition, an evaluation of non-traditional methods of forest protection against the spruce bark beetle (water spraying of whole landings, efficacy of insecticidal sraying of whole landings, and the use of insecticidal nets) was conducted and the possibility of the spruce bark beetle s sex determination was also examined.
When comparing the systems of pheromone traps installation, (1) the standard way was along the stand edge with 20 m space and (2) traps concentrating in the centre of clear cut adjacent to each other with different baiting, the most effective way was found to be the standard trap arrangement and the system with traps installed in line with the dispenser in each pheromone trap. Efficacy decreased with a lower number of pheromone dispensers. The influence of increased amounts of evaporated pheromone on efficacy was tested. Pheromone traps with one, two or three dispensers were compared and it was found that a trap s efficacy was not increased with a higher amount of released pheromone. The Pheagr IT and IT Ecolure Tubus dispensers showed unchanged effectivity throughout the flight activity of spruce bark beetle, but other dispensers need to be replaced according to the instructions since their efficacy decreases, thus affecting the swarming curve. Trying to determine the sex of the spruce bark beetle by selected morphological parameters shows that the gender can only be reliably determined by an autopsy of genitals.
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Comparison of the species spectrum of spruce bark beetle pathogens and its predators from genus Thanasimus caught in pheromone traps
Šídová, Michaela ; Lukášová, Karolína (advisor) ; Holuša, Jaroslav (referee)
Spruce bark beetle (Ips typographus (Linnaeus, 1758)) is our most serious pests, frequently invading spruce stands. The most important predators of I. typographus are two species from genus Thanasimus - Thanasimus formicarius (Linnaeus, 1758) and Thanasimus femoralis (Zetterstedt, 1828). Monitoring of these three species were carried out from April to August, using pheromone traps type Theyson with pheromone lures designed for their capture. New pheromone lure attracting beetles of genus Thanasimus has been tested. It was used a total of six traps that were placed at three locations. Two traps were always placed at one location, one with pheromone lure Pheroprax attracting spruce bark beetles and the second one with pheromone lure called Thanasiwit attracting beetles of the genus Thanasimus. All traps were checked once a week. A total of 10 291 of spruce bark beetles were captured, 25 specimens of T. formicarius and 7 individuals of T. femoralis. Spruce bark beetle flight activity had two generations and one sister brood. The first catches were recorded on 26 April 2015 and the end of the flight activity was recorded on 26 July 2015. The species T. formicarius flight activity was from 12 April 2015 to 2 August 2015 and during this period two generations were recorded. For T. femoralis flight activity was from 17 April 2015 until 9 August 2015, during this period we also recorded two generations, which took place before and after the flight activity of I. typographus. Laboratory work was conducted after the end of captures. From every of sample twenty individuals were dissected and then inspected using a light microscope to presence of pathogens. The most frequently identified pathogen of spruce bark beetles were nematodes, but only in one case nematods were identified in T. formicarius. Other pathogens were found only in the spruce bark beetles and they included microsporidia Chytridiopsis typographi, neogregarine Mattesia schwenkei and nematodes of the genus Contortylechus sp.
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Verification of fenological model of Ips typographus in the Czech Republic
Haramul, Michael ; Boublík, Karel (advisor) ; Holuša, Jaroslav (referee)
During the months of April and June 2014 the spruce bark beetle (Ips typographus L.) capturing was conducted into the pheromone traps followed by the verification of phenological model PHENIPS altogether at two study locations in the Czech Republic: Horní Planá in the southern Bohemia and Lipník nad Bečvou in the Olomouc region. The trapping was performed weekly with the help of pheromone tabular traps Theysohn which were equipped by pheromone-type evaporators Pheroprax from Chemipan. The aim of the study was to verify the validity of phenological model PHENIPS for the spruce bark beetle in the Czech Republic and verify whether the model is applicable for the Czech Republic. At the end of the 2014 season with the help of phenological models PHENIPS and the number of trapped bark beetle specimen the term of swarming and the term of colonization of host trees were determined. The sister generation activity was probably recorded in the several traps.
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Final report on the project: Diapause in the spruce bark beetle, Ips typographus, possible way to increase the effectiveness of protective measures
Doležal, Petr ; Davídková, M. ; Okrouhlík, Jan ; Bartošová, E. ; Štefková, Kristýna
The project broadens our knowledge on ecophysiology of the spruce bark beetle, mainly in relation to practical application of the results. As a main practical result of the project, several alterations that improved the effectiveness of currently applied protective measures have been proposed, tested and accepted by the headquarters of the Forests of the Czech Republic, state enterprises.
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Morphology and development of the midgut pathogens in bark beetle
TONKA, Tomáš
The bark beetle, Ips typographus is economically important pest of spruce standings across Europe. The knowledge of biology and ecology of bark beetles is important to protect spruce forests against beetles outbreaks. The research of pathogens of bark beetles is the main goal to use biological control of bark beetles and replace chemical or mechanical methods using today. During the bark beetle outbreak in Sumava mountains three main pathogens showed up very promising. Microsporidium Chytridiopsis typographi, the virus Ips typographus Entomopoxvirus and negregarine Menzbieria chalcographi were the most occured pathogens attacking beetles in Sumava outbreak area. Transmission of microspo ridium and virus have been introduced and propagated in living bark beetles in labo ratory. The reaserach of biology, transmission, morphogenesis and ultrastructure of these pathogens begun in living beetles in laboratory conditions. Results which were obtained can be divided to virological and microsporidian parts. In both cases the infection and routine passage have been successful in laboratory condition and now the infections of microsporidium Ch. typographi nad ITEV are routinely propagated to purchase infected material. Unlike the original description of ITEV in laboratory infected beetles the synthesis and origin of microspindles was described. In TEM the first steps of newly formed virions occluded into the spheroid were observed, including microspindles occlusion. ITEV develops in midgut epithelium of host. The successful infection of Ch. typographi has been managed in laboratory. Obtai ned results completed and revised findings which were published in first descriptions. Purchased results offer a possibility to compare old a new findings concernig this microsporidium. Budding as a unique process of multiplication has been described in microsporidia. This process is uncommon in microsporidia and has not never been observed. It acts as a tool to multiple vegetative stages in the life cycle. The ultrastructures and complete life cycle was described in Ch. typographi and the former description was revised.
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