?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Improvement+of+late+blight+management+in+organic+potato+production+systems+in+Europe%3A+field+tests+with+more+resistant+potato+varieties+and+copper+based+fungicides&rft.creator=Speiser%2C+B.&rft.creator=Tamm%2C+L.&rft.creator=Amsler%2C+T.&rft.creator=Lambion%2C+J.&rft.creator=Bertrand%2C+C.&rft.creator=Hermansen%2C+A.&rft.creator=Ruissen%2C+M.+A.&rft.creator=Haaland%2C+P.&rft.creator=Zarb%2C+J.&rft.creator=Santos%2C+J.&rft.creator=Shotton%2C+P.&rft.creator=Wilcockson%2C+S.&rft.creator=Juntharathep%2C+P.&rft.creator=Ghorbani%2C+R.&rft.creator=Leifert%2C+C.&rft.subject=Crop+health%2C+quality%2C+protection&rft.description=Late+blight+of+potatoes%2C+caused+by+Phytophthora+infestans%2C+is+particularly+difficult+to+prevent+or+control+in+organic+agriculture.+In+this+study%2C+the+host+resistance+of+selected+varieties+to+foliar+and+tuber+blight+and+their+yield+under+organic+growing+conditions+were+assessed+in+trials+carried+out+in+four+countries+(Switzerland%2C+France%2C+England+and+Norway)+in+2001+and+2002.+The+objective+was+to+identify+new%2C+more+resistant+varieties+which+might+replace+some+of+the+more+susceptible+varieties+which+are+currently+grown+in+organic+agriculture.+In+each+country%2C+five+test+varieties+were+compared+with+two+reference+varieties%2C+identical+for+all+sites%2C+and+with+two+locally+popular+varieties.+In+addition%2C+the+effect+of+copper+fungicides+was+assessed+for+all+varieties+in+England.+Several+new+potato+varieties+(Appell%2C+Derby%2C+Innovator+and+Naturella+in+Switzerland%3B+Derby%2C+Eden%2C+Escort+and+Naturella+in+France%3B+Sarpo+Axona%2C+Eve+Balfour%2C+Lady+Balfour%2C+Sarpo+Mira+and+Sarpo+Tominia+in+England%3B+N89-1756+and+N92-15138+in+Norway)+proved+far+less+susceptible+to+foliar+and+tuber+blight+than+most+of+the+varieties+currently+grown.+However%2C+market+requirements+could+restrict+their+introduction+into+practice.+The+copper+fungicide+treatment+reduced+foliar+blight+severity+in+all+varieties+tested+in+England+and+in+both+years%2C+by+27%25+on+average%2C+and+increased+yield+by+20%25+on+average%2C+but+did+not+affect+tuber+blight.%0D%0AIn+organic+farming%2C+a+shift+towards+the+use+of+blight+resistant+varieties+should+thus+be+strongly+encouraged%2C+although+this+is+unlikely+to+eliminate+the+need+to+use+copper+fungicides.&rft.date=2006&rft.type=Journal+paper&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.identifier=http%3A%2F%2Forgprints.org%2F8358%2F1%2FSpeiser_etal_2006_late_blight.pdf&rft.identifier=Speiser%2C+B.%3B+Tamm%2C+L.%3B+Amsler%2C+T.%3B+Lambion%2C+J.%3B+Bertrand%2C+C.%3B+Hermansen%2C+A.%3B+Ruissen%2C+M.+A.%3B+Haaland%2C+P.%3B+Zarb%2C+J.%3B+Santos%2C+J.%3B+Shotton%2C+P.%3B+Wilcockson%2C+S.%3B+Juntharathep%2C+P.%3B+Ghorbani%2C+R.+and+Leifert%2C+C.+(2006)+Improvement+of+late+blight+management+in+organic+potato+production+systems+in+Europe%3A+field+tests+with+more+resistant+potato+varieties+and+copper+based+fungicides.+Biological+Agriculture+and+Horticulture+(Vol.+23)%2C+pp.+393-412.&rft.relation=http%3A%2F%2Forgprints.org%2F8358%2F