Morphology and development of the midgut pathogens in bark beetle

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