title: Efficacy of a Juncus effusus extract on grapevine and apple plants against Plasmopara viticola and Venturia inaequalis, and identification of the major active constituent.
abstract: BACKGROUND
  There is growing demand to replace chemical pesticides with alternatives owing to concerns related to impacts on human health and the environment. Plant-derived plant protection products could provide sustainable and environmentally friendly alternatives to chemical products. The aim of this study was to identify plant and fungal extracts with so far unknown activity against important plant pathogens by in vitro screening of a library of more than 3000 extracts.
  
  
  RESULTS
  Several plant extracts with promising in vitro fungicidal activity (MIC100 ≤ 50 µg mL(-1) ) towards one or several of the investigated pathogens (Venturia ineaqualis, Phytophthora infestans, Plasmopara viticola) were identified by the screening. One of the hits, an ethyl acetate extract of Juncus effusus L. medulla, was further investigated, and dehydroeffusol (DHEF) was identified as its main active constituent. On susceptible grapevine and apple seedlings, efficacies of up to 100% were reached with the extract (EC50 123 or 156 µg mL(-1) ) and with DHEF (EC50 18 or 21 µg mL(-1) ) against P. viticola and V. inaequalis respectively.
  
  
  CONCLUSIONS
  Our results demonstrate that plants can provide promising alternatives for integrated and organic farming. J. effusus shows high efficacy at low concentrations and, as an abundant perennial species, is an interesting candidate for the development of a novel plant protection product. © 2015 Society of Chemical Industry.
authors.affiliation: Research Institute of Organic Agriculture FiBL, Frick, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Thuerig
authors.affiliation: Department of Pharmaceutical Biology, University of Basel, Basel, Switzerland.
authors.forename: Justine
authors.initials: J
authors.lastname: Ramseyer
authors.affiliation: Department of Pharmaceutical Biology, University of Basel, Basel, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Hamburger
authors.affiliation: Research Institute of Organic Agriculture FiBL, Frick, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Oberhänsli
authors.affiliation: Department of Pharmaceutical Biology, University of Basel, Basel, Switzerland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Potterat
authors.affiliation: Research Institute of Organic Agriculture FiBL, Frick, Switzerland.
authors.forename: Hans-Jakob
authors.initials: HJ
authors.lastname: Schärer
authors.affiliation: Research Institute of Organic Agriculture FiBL, Frick, Switzerland.
authors.forename: Lucius
authors.initials: L
authors.lastname: Tamm
mesh_terms: D001203:Ascomycota / Q000187:drug effects*; D019684:Magnoliopsida / Q000737:chemistry*; D027845:Malus / Q000382:microbiology*; D009868:Oomycetes / Q000187:drug effects*; D055750:Phytophthora infestans / Q000187:drug effects; D010935:Plant Diseases / Q000382:microbiology*; D010936:Plant Extracts / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology; D027843:Vitis / Q000382:microbiology*
chemical_list: D010936:Plant Extracts
keywords: Juncus effusus; apple scab; dehydroeffusol; downy mildew; fungicide; plant extract