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Measurement of predator effectiveness by means of cage exclusion experiments
Fischerová, Laura ; Kindlmann, Pavel (advisor) ; Tropek, Robert (referee)
1 Abstract Cage exclusion experiments are used in ecological and agricultural studies to determine plant- insect interactions (Kidd & Jervis 2005). Cages are used to detect the insect density on the plant, while other influences such as natural predators or other pests are excluded. Exclusion of predators by using physical barriers (different mesh size) is one of the most used ways to determine the impact of natural enemies on the pest population. The results of these experiments suggest, that the pest population on caged plants, from which natural enemies are excluded, has a lower percentage of mortality and parasitism than the population on plants, where the natural enemies have full access to (Luck et al. 1988). Results of this method are used in programs of biocontrol when searching optimal plant treatments and possible alternatives instead of using insecticides (Lawson et al. 1994). The question is, whether cage exclusion experiments are adequately reflecting changes in pest populations and their impact on plants. As a result of caging the area, changes in microclimate and plant growth occur, which subsequently affects present insect populations. Cages do not also allow leaving the pests from the cage and, in some cases, unwanted natural enemies enter them, even though they have been previously...
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Measurement of predator effectiveness by means of cage exclusion experiments
Fischerová, Laura ; Kindlmann, Pavel (advisor) ; Tropek, Robert (referee)
1 Abstract Cage exclusion experiments are used in ecological and agricultural studies to determine plant- insect interactions (Kidd & Jervis 2005). Cages are used to detect the insect density on the plant, while other influences such as natural predators or other pests are excluded. Exclusion of predators by using physical barriers (different mesh size) is one of the most used ways to determine the impact of natural enemies on the pest population. The results of these experiments suggest, that the pest population on caged plants, from which natural enemies are excluded, has a lower percentage of mortality and parasitism than the population on plants, where the natural enemies have full access to (Luck et al. 1988). Results of this method are used in programs of biocontrol when searching optimal plant treatments and possible alternatives instead of using insecticides (Lawson et al. 1994). The question is, whether cage exclusion experiments are adequately reflecting changes in pest populations and their impact on plants. As a result of caging the area, changes in microclimate and plant growth occur, which subsequently affects present insect populations. Cages do not also allow leaving the pests from the cage and, in some cases, unwanted natural enemies enter them, even though they have been previously...
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