Effect of pest management systems on foliage- and grass-dwelling spider communities in an apple orchard in Hungary

Abstract

Spider communities (Araneae) inhabiting the canopy, the herbaceous layer and the borders, as well as the populations overwintering on the tree trunks of different aged IPM and conventional apple orchards were investigated in Hungary. Abundance and species richness of entire spider communities in IPM plots were significantly higher than in conventional plots, probably owing to the lower toxicity of pesticides used and higher prey densities. In the case of abundance, similar tendencies were observed in web-building and hunting spider guilds. Age of plantations can significantly influence spider density in the canopy, acting through the prey density. In young plantations, where size of the canopy was smaller and density of the pear lace bug (Stephanitis pyri L.) higher, significantly higher numbers of hunting spider communities were present than in old plantations which had been similarly treated. This relationship was not observed for web-building spiders. Diversity of canopy-inhabiting spider communities was higher in old plots, regardless of the treatments. The effect of the border of the orchard on spider communities was investigated and it was found that when selective insecticides were used, migration of spiders into orchards was increased significantly. When broad-spectrum insecticides were applied, spider densities in the canopy did not differ between outer and inner rows of the orchards. The effect of the treatments and orchard age, both on abundance and species richness of overwintering spider communities on the trunk, showed the same result as for canopy spiders, namely significantly larger spider communities were found in IPM plots and in the young plantation than in conventionally-treated plots and in the old plantation. Broad-spectrum insecticides reduced abundance and species richness of spider communities in the herbaceous layer of the conventionally-treated plot. At the same time, the spider communities of the herbaceous layer of the IPM plot did not differ significantly from adjacent herbaceous plants. A significant overlap exists between spider communities of the canopy and herbaceous layer. Despite chemical treatments, migration from the herbaceous layer into the canopy occurs. The effects of chemical treatments on the dominant species are discussed. There were no significant differences between the differently treated plots in abundance of one of the dominant species Oxyopes heterophthalmus Latreille. However, the other dominant species, Cheiracanthium mildei L. Koch, was more abundant in the IPM plots.

Change in the community of epigeal spiders and harvestmen (Araneae, Opiliones) with the age of an apple orchard

“…This is in agreement with results of this study. Bogya et al (2000) found higher diversity of spiders in older orchard but higher density of spiders in the young one. Hurd and Fagan (1992) compared density and diversity of cursorial spiders on several successional stages of pastures.…”

“…Several other studies centred upon spiders of the understorey plants (e.g. Bogya et al 2000) and only few papers dealt with epigeal community of arachnids in orchards (Holstein and Funke 1995, Pekár 1999b.…”

Organic versus conventional management in an apple orchard: effects of fertilization and tree‐row management on ground‐dwelling predaceous arthropods

“…insecticides ( Bogya et al , 2000;Epstein et al , 2000;Markó & Kádár, 2005 ); but see also Bogya and Markó (1999) . Other management aspects, such as groundcover management, also have an impact on ground-dwelling predators ( Miñarro & Dapena, 2003;Mathews et al , 2004 ).…”

Population models in pesticide risk assessment: Lessons for assessing population‐level effects, recovery, and alternative exposure scenarios from modeling a small mammal

“…Goh et al [22] observed 48% fewer earthworm biomass in commercial orchards compared with organic orchards. Ground-dwelling spider abundance in commercial apple orchards in Hungary was only 33.9% of the abundance in the edge (weed cover) neighboring the orchard (23; see also Boyga and Marko [24] for similar results). In summary, it can be assumed that food abundance in commercial orchards is at least 50% less than reported by Churchfield [20] for natural grassland.…”