Evaluation of the Efficacy of the Fungicide difenoconazole + cyflufenamid (Cidely-Top® DC 140) against Golovinomyces cichoracearum, Causal agent of Cucumber Powdery Mildew Disease

Efficacy of difenoconazole+cyflufenamid (Cidely-Top® DC 14%) in control of cucumber powdery mildew, caused by Golovinomyces cichoracearum was evaluated using RCBD with 6 treatments and 4 replications in Alborz, Tehran and Khuzestan provinces. Treatments included 0.8, 0.9 and 1 ml L-1 of Cidely-Top®, tetraconazol (Domark® EC 10%) 0.4 ml L-1, bicarbonate potassium (Kaliban® SL 85%) 5 g L-1 along with no spraying control. Foliar sprayings started once early symptoms appeared and followed up at 5-10 days intervals. The data noted before each spraying and 14 days after the last spraying as the DSI by using Horsfall and Barrat scale from 1-7. Mid-point was using for each plant. AUDPC was calculated for each plot, too. Data were analyzed by SAS software and means were compared using DMRT (P=5%). Comparison of the efficacy of treatments based on the AUDPC which displays cumulative percentage of disease during a 36 days period revealed that Cidely-Top®  0.8, 0.9 and 1 ml L-1 have reduced the AUDPC by 74.9%, 81.2%, and 85.2% respectively in comparison with the control. Meanwhile, the Domark® at the rate of 0.4 ml L-1 resulted in the efficacy of 82.7% and Kaliban® also showed the least amount of efficacy (59.8%) compared with the control. Based on the results obtained from this research, the fungicide Cidely-Top® may be recommended to be used at 0.8 ml L-1 for 5 to 7 days intervals, at 0.9 ml L-1 for 7 to 10 days intervals and at 1 ml L-1 for up to 14-days intervals.