Efficacy of Various Commercial brands of Bordeaux mixture in the Control of Downy Mildew of Greenhouse Cucumber, Pseudoperonospora cubensis

Downy mildew disease caused by fungal-like Pseudoperonospora cubensis is one of the most destructive disease of cucumber cultivated in greenhouses. In the present study efficacy of four commercial brands of Bordeaux mixture in two doses of 4 and 5 ml/L as target fungicides and propamocarb hydrochloride + fluopicolide (Infinito® 68.75 SC) at the rate of 2ml/L and Cyazofamid (Ranman® SC 400) at the rate of 0.5 ml/L as standard fungicides in controlling of cucumber downy mildew disease were assessed. Experiments were carried out in Tehran and Mazandaran provinces in a Randomized Complete Block Design (RCBD) with 4 replications. Foliar applications of fungicides started once after the early symptoms appearance and followed up at 7-10 days intervals and were repeated for three times in Tehran and four times in Mazandaran provinces. The disease severity was assessed based on a scale described by Thomas et al. Data were analyzed using SAS software and the means were compared using Duncan's multiple range test. Comparison of the complex average percentage of disease severity in the provinces of Tehran and Mazandaran shows that Ranman fungicide (0.5 ml/L), Bordotex (5 ml/L) and Infinito (2 ml/L) show decrease in disease severity by 79.1, 75.8 and 72.8% respectively and were effective in controlling the disease compared with water spray treatment. Meanwhile the results reveal that Bordoxin (5 ml/L), Bordotex (4ml/L), Bordosafe (4 and 5 ml/L) and Bordofix (5 ml/L) showed  67.4, 65.3, 60.1, 62.2 and 59.2% efficacy in comparison with water spray control respectively and were ranked after the other three brands. Therefore it is concluded that doses of 4 and 5 ml/L of Bordotex and Bordosafe and the dose of 5 ml/L of Bordoxin and Bordofix are appropriate rates to controlcucumber downy mildew disease.