Efficacy of cyazofamid (SC 400) Fungicide in the Control of Downy Mildew of Greenhouse Cucumber

Downy mildew caused by Pseudoperonospora cubensis is one of the most important diseases ofgreenhouse cucumber which causes significant economic losses in Iran annually. For the assessment of cyazofamid (Ranman® SC 400) efficacy on the control of this disease as a new and safe fungicide, three locations in Yazd province with precedent infection were selected and in situ assays were carried out with 5 treatments and four replications during the years 2010 and 2011. Treatments included Ranman in doses of 0.2, 0.3 and 0.4 ml/1000L, Famoxadone 16.6%) Cymoxanil (22.1%) (Equation® pro WDG 52.5%) at a rate of 0.3 g/1000L when the first symptoms of the disease was observed and the results were compared with the control without spraying. The disease severity was assessed when the disease percentage in the control treatment was estimated at 50%. Data were analyzed by SAS software and Duncan's multiple range tests used for mean comparison. Results indicated that fungicide application caused significant decrease in the disease severity compared to control treatment. The highest disease control occurred in treatment of cyazofamid at 0.4 ml/1000L (75.77%) and 0.3 ml/l followed by Equation pro at 0.3 g 1000L (68.48 and 66.6% respectively) application rates. The lowest control percent was that of cyazofamid at 0.2 ml/1000L application rate (40.91%). In conclusion, cyazofamid at 0.3-0.4 ml/1000L is recommended for the disease control.