Conference paper, poster, etc. #40894

Summary translation

Grape production systems must adapt to reduce the quantities of pesticides used because of itsnegative effect on environment. Organic viticulture may be one solution to face this issue. But to drasticallyreduce pesticide use, innovative organic practices are required in every soil and climate conditions. In a contextof transition to Innovative Organic Viticulture (IOV), changing practices can strongly affect the agronomicperformances of grape production. In this study, we analyzed the performances of organic grape productionsystems during the transition to IOV. Published methods are used to assess yield and grape quality. Anexperimental network with 7 studied cases located in Northeastern and in Mediterranean area, in France, hasbeen set up since 2013. Each case was studied during three years of transition to IOV. The cases tested dealtwith conversion to organic or with introducing innovative practices in organic cases (Metral et al., 2012). InMediterranean area, the cases were planted with Grenache grapevine variety to produce Protected Designationof Origin Côte du Rhône. In Alsace, the cases were planted with Riesling grapevine variety to produceProtected Designation of Origin Alsace for two cases (CHA and ING) and Grand Cru Osterberg for the thirdcase (RIB). CHA case is a cooperative production; whereas all the other cases are private wineries. The resultssupport that most of the studied cases succeed in expected yield and grape quality for Protected Designation ofOrigin wine production in very different soil and climate conditions. In all Alsace cases and in most ofMediterranean cases, the yield ratios were satisfactory the 3-yeared of observation because estimated yieldmatch with target yield. The diminution of yield ratio in CHA matches with the winegrower goal. Indeed, thewinegrower introduced innovative practices to reduce yield together with drastically reduce copper fungicideuse. In Mediterranean area, three of the four cases have acceptable yield ratio (VERR, SERG and VIN). Theexception of year2 in VIN case is due to a regional pathogen accident: black-rot attack exploded in Rhonevalley and winegrower didn't manage to use pesticide to protect grapevines. The black-rot attack induced directloose of 64% of the VIN yield in year2. In year3, VIN strategy was a success to struggle against black rot: thewinegrower managed the pesticide use very precisely to avoid a too high lack of yield. GUE case never reachedthe target yield. The winegrower strategy is ‘use zero pesticide’ and to accept yield loose. According to this, theestimated yield is not so inacceptable in year1 and in year2. The exception of year3 in GUE case is due to thesame regional black-rot accident as VIN case in year2. Whatever the chosen innovative pesticide strategy, thereis still a huge risk of yield loose not depending in the case of a large fungi regional attack. The three years goodyield ratio of VERR and SERG cases is partly due to medium pathogens attacks. The quality results supportthat most of the studied cases succeed in expected sugar rate according to the different PDO conditions. Just onexception was observed: GUE sugar rate was the lowest. Maturity of berries was not reached even if yield ratiosatisfied the winegrower. In this study, we demonstrated that the success of organic grape production isguaranteed in most of the studied cases. The target yield and target sugar rate are achieved in very differentvineyard areas conditions. Equally, year climate, latitude climate and PDO conditions are appropriated tospread out Innovative Organic Viticulture.