title: Pesticide seed dressings can affect the activity of various soil organisms and reduce decomposition of plant material.
abstract: Seed dressing with pesticides is widely used to protect crop seeds from pest insects and fungal diseases. While there is mounting evidence that especially neonicotinoid seed dressings detrimentally affect insect pollinators, surprisingly little is known on potential side effects on soil biota. We hypothesized that soil organisms would be particularly susceptible to pesticide seed dressings as they get in direct contact with these chemicals. Using microcosms with field soil we investigated, whether seeds treated either with neonicotinoid insecticides or fungicides influence the activity and interaction of earthworms, collembola, protozoa and microorganisms. The full-factorial design consisted of the factor Seed dressing (control vs. insecticide vs. fungicide), Earthworm (no earthworms vs. addition Lumbricus terrestris L.) and collembola (no collembola vs. addition Sinella curviseta Brook). We used commercially available wheat seed material (Triticum aesticum L. cf. Lukullus) at a recommended seeding density of 367 m(-2).
  
  
  
  Seed dressings (particularly fungicides) increased collembola surface activity, increased the number of protozoa and reduced plant decomposition rate but did not affect earthworm activity. Seed dressings had no influence on wheat growth. Earthworms interactively affected the influence of seed dressings on collembola activity, whereas collembola increased earthworm surface activity but reduced soil basal respiration. Earthworms also decreased wheat growth, reduced soil basal respiration and microbial biomass but increased soil water content and electrical conductivity.
  
  
  
  The reported non-target effects of seed dressings and their interactions with soil organisms are remarkable because they were observed after a one-time application of only 18 pesticide treated seeds per experimental pot. Because of the increasing use of seed dressing in agriculture and the fundamental role of soil organisms in agroecosystems these ecological interactions should receive more attention.
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria. johann.zaller@boku.ac.at.
authors.forename: Johann G
authors.initials: JG
authors.lastname: Zaller
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria.
authors.forename: Nina
authors.initials: N
authors.lastname: König
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Tiefenbacher
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Muraoka
authors.affiliation: Institute of Zoology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria.
authors.forename: Pascal
authors.initials: P
authors.lastname: Querner
authors.affiliation: Institute for Seed and Propagating Material, Phytosanitary Service and Apiculture, Austrian Agency for Health and Food Safety (AGES), Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Ratzenböck
authors.affiliation: Department of Terrestrial Ecology, Institute of Zoology, University of Cologne, Cologne, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Bonkowski
authors.affiliation: Department of Terrestrial Ecology, Institute of Zoology, University of Cologne, Cologne, Germany.|Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Koller
mesh_terms: D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D017753:Ecosystem; D056890:Eukaryota / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D010575:Pesticides / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry* / Q000254:growth & development; D012987:Soil / Q000469:parasitology*; D012988:Soil Microbiology; D014908:Triticum / Q000737:chemistry / Q000254:growth & development
chemical_list: D010575:Pesticides; D012987:Soil
keywords: Agricultural intensification; Agroecosystems; Belowground; Difenoconazole; Ecotoxicology; Fludioxonil; Imidacloprid; Pesticides; Prothioconazole; Soil ecology