Studies of the sensitivity level of dead-arm (Phomopsis viticola) disease against copper compounds on seedless grapes in Manisa province

Cane and leaf blight of grapevines caused by the fungus P.viticola is an important disease in several viticultural regions of the world. In the recent years growers have reported a reduction in efficacy of copper compounds traditionally used to control cane and leaf blight. In this study, 29 isolates of P. viticola were tested for copper sulphate and copper hydrokside. The all isolates of P. viticola were isolated from infected cane (Vitis vinifera L. cv 'Sultana Seedless') obtained from vineyards in Manisa (Turgutlu, Salihli, Alasehir, Sarıgol (50 different locations screened and they were isolated 29 locations )) province. Copper sensitivity testing was done by measuring mycelial area and calculating EC50 and MIC values. Minimum inhibitory concentration (MIC) values for 29 isolates were found to range from 1 to 6 mM for copper sulphate to 10-20 mM for copper hydroxide. The mean of concentrations inhibiting 50% of growth (EC50) values for the studied isolates were 1.1 mM for copper sulphate. Results showed that of 29 isolates screened, 7 isolates were tolerant to copper sulphate and 13 isolates were sensivity to copper sulphate. According to results copper sulphate has shown a beter effect than copper hydroxide.