Side effects of kaolin particle films on apple orchard bug, beetle and spider communities

Abstract

The effects of multiple applications of hydrophobic kaolin particle film on apple orchard bug (Heteroptera), beetle (Coleoptera) and spider (Araneae) assemblages were studied in the Netherlands. Insecticide-free orchard plots served as a control. The kaolin applications significantly reduced the abundance and species richness of the communities and also altered their composition and diversity. The treatments disrupted many non-target groups notably mycophagous, predacious and tourist beetles, zoophagous bugs and spiders. Among spiders, wanderer spiders (Thomisidae, Philodromidae) were most affected, whereas web building spiders (Dictynidae) were least affected. After ceasing the applications in July, the between-treatment differences in composition of all communities and diversity of heteropterans and spiders diminished while the differences in abundance and species richness remained for a long time, until the end of September. Many predator species with good colonisation ability recovered slowly after the treatments, mainly due to the scarcity of prey.

Keywords:

• kaolin particle film
• non-target effect
• apple orchard
• Heteroptera
• Coleoptera
• Araneae
• community
• organic pest management

Acknowledgement

We would like to thank Andy Benger, Mark Jervis and two anonymous reviewers for their helpful comments and suggestions. This study was supported by Engelhard Corporation, Iselin, NJ, USA and partly by OTKA (75856).