Bibliography
2021
© Oto Zimmermann
Authors
František Kocourek, RNDr. Milan Řezáč, Ph.D.
Abstract
The effects of three different pest control regimes in three pear orchards (two with integrated pest management regimes and one with an organic farming regime) on communities of arthropods were studied in a two-year experiment. Insects were collected in three stages by beating the lower branches of trees. The number of species and other taxa of natural enemies increased with the reduction in insecticide applications. A total of 2,492 individuals of 145 species and other taxa were found in the samples from the three pear orchards with different pest management practices. The most numerous groups were Araneae, with 44 species, and Coleoptera, with 42 species, followed by Hymenoptera, with 33 taxa, and Heteroptera, with 24 species. Of the total number of taxa, the share of entomophagous arthropods was, on average, 62.6%. The share of predaceous individuals was, on average, 63.7% of the total number of individuals. The  number of dominant predaceous species decreased with an increase in the diversity of species and other taxa. A significant relationship was found between the number of C. pyri adults and the Shannon-Wiener index of diversity for the predaceous taxa. It was demonstrated that generalist predators and their diversity have an important influence on the regulation of pear psylla in the vegetative period.

2006
© Oto Zimmermann
Authors
František Kocourek, RNDr. Milan Řezáč, Ph.D., prof. Mgr. Stanislav Pekár, Ph.D., prof. Mgr. Stano Pekár, Ph.D.
Abstract

The effect of two strategies, used to control Ostrinia nubialis, on the abundance and diversity of epigeic spiders and harvestmen in maize was monitored. The two strategies were transgenic insect-resistant maize, and biological control by Trichogramma wasps on an isogenic maize hybrid. They were compared with a conventional system (isogenic maize hybrid), which was taken as the control. The investigation was performed at two localities (Ivanovice na Hané and Prague) in the Czech Republic from 2002 to 2004. Spiders (Araneae) and harvestmen (Opiliones) were collected by means of pitfall traps. We found that the annual abundance and diversity of arachnids on plots with the two strategies were not significantly different from a conventional system. The overall abundance of spiders decreased over three years in all systems. There was no difference in the family and guild (hunters versus web-builders) composition between strategies and the conventional system. A displacement of linyphiid spiders with lycosids on all plots over time was observed. This change is attributed to the existence of a sparse weed cover of maize fields as a result of consecutive monocultural planting.


2006
Authors
František Kocourek, RNDr. Milan Řezáč, Ph.D., prof. Mgr. Stanislav Pekár, Ph.D., prof. Mgr. Stano Pekár, Ph.D.
Abstract
Originalni ID: 141

2004
© Ondřej Machač
Authors
František Kocourek, prof. Mgr. Stanislav Pekár, Ph.D., prof. Mgr. Stano Pekár, Ph.D.
Abstract
Two management systems, biological and integrated, were compared to control the major pest, codling moth (Cydia pomonella) in apple orchards. The aim of the study was to assess the effect of these two systems on arboreal spiders. The biological system was based on the use of biological preparations, whereas in the integrated system selective pesticides were employed. The control plot had no pesticide treatment. The abundance of spiders was similar in all study plots during 3 years of study. Diversity, however, was higher in the biological plot than in the control and the integrated plots, suggesting that the response of spiders to management was guild-specific. Four spider families dominanted in all plots: Araneidae (orb weavers), Theridiidae (space-web weavers), and Philodromidae and Thomisidae (ambushers). While Araneidae and Thomisidae were similarly abundant on all plots, the density of Theridiidae and Philodromidae differed. In the integrated plot there were significantly more theridiid spiders, whereas in the control plot philodromid spiders were significantly more abundant. On the biological plot, the two families were similarly abundant. These differences were attributed to different age of trees in the control and treated plots, different prey spectrum, different susceptibility of the two families to applied chemicals and intraguild predation of theridiids by philodromids.

Statistics

Found

809
Records
101
Species
63
Genera
3
Squares