Effect of sowing dates on development of cucumber downy mildew under low plastic tunnel

Effect of sowing dates on development of cucumber downy mildew under low plastic tunnel was studied on cucumber cultivar Punjab Naveen during 2008–09 and 2009–2010 at Ludhiana. All the sowing dates significantly affected the disease severity and fruit yield. During 2008–09, data revealed that disease severity was significantly less (40.16%) in crop sown on 15^th December than that recorded in crop sown on 30^th December (48.03%), 15^th January (51.46%) and 30^th January (53.50%). Maximum fruit yield (16.30 kg/plot) was recorded in the crop sown on 15^th December followed by 30^th December (12.75 kg/plot), 15^th January (10.25 kg/plot) and 30^th January (6.33 kg/plot) respectively. During 2009–10 maximum disease severity (52.83%) was recorded in the crop sown on 30^th January and minimum (37.06%) in the crop sown on 15^th December. Maximum fruit yield (17.50 kg/plot) was recorded in the crop sown on 15^th December than that sown on 30^th December (13.34 kg/plot), 15^th January (11.32 kg/plot) and 30^th January (6.80 kg/plot). Disease severity values were significantly different at 5% level of significance. Maximum rate of disease progress (0.066) was recorded in the crop sown on 30^th January and minimum (0.051) in the crop sown on 15^th December. Area under disease progress curve (AUDPC) was recorded minimum (110.53) in the crop sown on 15^th December and maximum (157.92) in the crop sown on 30^th January. From the results obtained in the present study, it was concluded that disease severity increased with delay in date of sowing.