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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Závislost vybraných antagonistů na početnosti Lymantria dispar / Dependence of selected antagonists on Lymantria dispar abundance

Jelínková, Zuzana January 2016 (has links)
The aim of this study was to investigate the dependence of selected antagonists to the abundance of Lymantria dispar. The aim of the study was to determine whether these natural enemies can affect the abundance of L. dispar. I have focused on South Moravia, where L. dispar occurs. In 2015 the Turček method reviewed a total of 3,600 trees in seven locations with the historical appearance of outbreaks of gypsy moth. Density egg clutches were extremely low, about 0.019 for each new clutch per tree, which corresponds to the latent state. On the studied locations egg clutches was collected, measured and recorded in notebooks. A load with at least one egg in each area was removed with the top 5 cm of litter and a top layer of mineral soil. The removed soil was put into pots in which were stored late instar caterpillars for the detection of E. maimaiga. The cups were inserted along with the caterpillars in the refrigerator for three days at 15°C without food. Aafter three days the caterpillars were taken away individually and placed on an artificial diet. An inspection was performed and a their mortality was monitored. The presence of E. maimaiga was examined microscopically for 325 dead caterpillars, but no pathogen was detected. In the laboratory, the individual egg clutches were placed upon a Petri dishes with filter paper and the number of eggs counted with a stereo microscope. Subsequently, the eggs were left to hatch and were analyzed for the presence of parasitoids. A total of 1 246 species of egg parasitoids Anastatus japonicus was found in six locations, taking in donations females predominated. Egg parasitism was on average around 5%. Flight activity A. japonicus was quite long and covered the period 24 May 2015 to 28 July 2015. In the absence of E. maimaiga and low egg parasitism at the studied locations we do not expect any strong influence of the studied antagonists on population density and outbreak cycle L. dispar in South Moravia.

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