EFFECT OF SOWING DATE AND IPRODIONE ON THE ALTERNARIA BLIGHT OF MUSTARD (Brassica juncea)

Abstract

A field study had been carried out during the period from October 2006 to February 2007 at Syedpur in Nilphamari district to determine the effect of sowing date and Iprodione in controlling the Alternaria blight of mustard cv. Tori 7. The three sowing dates were 23 October (early), 07 November (normal) and 22 November (late), 2006. Iprodione (0.25%) was applied three times, viz. single spray, two sprays and three sprays at 10-days interval starting from the first disease initiation on the lower older leaves of 30-40 days old plants. Control plots were sprayed with plain water. The manipulation of early sowing date as non-monetary input decreased the leaf area diseased, pod area diseased, number of pod infection, number of spot per pod and increased 1000-seed weight, seed yield per plant and yield per hectare over late sowing. Results obtained in this study indicated a tremendous effect of sowing date on the disease severity and seed yield of mustard. The application of three sprays of Iprodione provided the maximum control of Alternaria blight and increased seed yield per hectare. Iprodione three sprays in combination with early sowing (23 October) displayed the best performance in controlling the Alternaria blight disease. Three sprays of Iprodione (0.25%) or 23 October (early) sowing alone significantly brought down the disease severity while in combination reduced the disease significantly and increased seed yield by 28.42 % over control (non-sprayed) of late sowing crop. Finally, it may be concluded that Iprodione three sprays in combination with early sowing was found superior for management of Alternaria blight of mustard oilseed crop.