摘要 : Field studies were conducted in Maharashtra, India, in 2005, to evaluate the influence of sowing dates on Yellow vein mosaic virus (YVMV) disease development, whitefly population build up and yield of okra and determine the suitab... 展开 Field studies were conducted in Maharashtra, India, in 2005, to evaluate the influence of sowing dates on Yellow vein mosaic virus (YVMV) disease development, whitefly population build up and yield of okra and determine the suitable sowing date that will have minimum disease incidence and highest yield. Monthly sowing using the cultivars Parbhani Kranti, AROH-10 and Local were conducted. The plots were exposed to natural invasion by whiteflies to develop the disease. Observations on the vector population, disease incidence and yield were recorded. The whitefly count was recorded from 7 to 120 days after sowing, with an interval of 7 days. The plants showing YVMV infection were marked at different growth stages and the percentage of disease incidence was worked out. Okra fruits were harvested regularly and weights were recorded. The yields in kg/ha were also calculated. Results of the effect of sowing date on whitefly and disease incidence and yield of okra revealed that the crop sown in August (kharif) had the highest yield (5827 kg/ha), with 1.02 whiteflies/leaf and 58.31% disease incidence. In summer, okra sown in February gave the highest yield of 4690 kg/ha with 0.69 whiteflies/leaf and 44.50% disease incidence. However, the crop sown in January, September, October, November and December recorded less whitefly and disease incidence than those sown in August and February, but the yield level in these months was not proportionally higher with the lower level of incidence. The crop sown in March, April, May, June and July recorded higher whitefly and disease incidence and lower yields. 收起