Field surveys were conducted in four districts of northern Karnatakaduring 2014-15 to assess the distribution and frequency of virusesinfecting cucumber. In the cucumber mosaic disease (CMD) infectedplants, dark green mottling and mosaic were typical symptoms,whereas zucchini yellow mosaic disease (ZYMD) produced darkgreen islands or blisters and vein banding as diagnostic symptoms.Tomato leaf curl disease (ToLCD) infected leaf samples showedbilstering, upward curling and crumpling of leaves as characteristicsymptoms. During survey it was notified that, Dharwad districtrecorded highest mean incidence of CMD (23.94 %) and ToLCD(3.14 %) whereas, Haveri district record highest mean incidence ofZYMD (6.79 %). The mean incidences of CMD, ZYMD and ToLCDin both the seasons were 22.84, 6.20 and 2.92 per cent respectively.The highest mean incidence (%) of viral diseases were recorded atharvesting stage in black soil under irrigated condition compared torainfed condition.