Influence of Date of Sowing and Boron Fertilization on Incidence of Yellow Vein Mosaic Virus in Kharif Okra, Abelmoschus esculentus

Background: Okra requires a long period of warm and humid weather. It may be cultivated effectively in hot, humid climates. It is susceptible to frost and very low temperatures. Temperatures between 24°C to 28°C are considered ideal for regular growth and development. Aim: The experiment was carrying the objective of establishment the relationship between incidence of YVMV and weather parameters during growing season of okra and to access the relation between YVMV incidence and boron application. Methodology: A field experiment was conducted at farmer’s field at Andharua Bhubaneswar with Okra (cv-lily) as test crop at two dates of sowing i.e., 30th January (D1) and 15th February 2021 (D2) with 10 boron treatments comprising of B-0, b-1.5kg/ha soil, 0.25%, 0.5%, 0.75%, 1.0% borax once and twice foliar spray in a low boron (0.35 mg/kg) and low fertile acidic soil. The crop experienced 109.7mm rainfall, 10 rainy days, 29.1°C-39.9°C Tmax, 13.2°C-27.3°C Tmin.The BSH was 2.7-8.1 hrs. Results: The emergence count, plant height, plant population and leaf area were better in D2. The fresh fruit yield of Okra varied from 6.52-9.15 t/ha where D2 produced more than D1. The boron content of fruit varied from 0.09 to 0.18mg/kg where T8 contain more boron. The YVMV PDI attend the peak 12.59-29.62 during the 2nd week of April at 77 DAS in D1(first date of sowing. Similarly in D2 (second date of sowing, the peak was attended at 63 DAS i.e., the 3rd week of April varied from 11.85-29.62%. From this experiment, out of seven weather parameters, Tmin and Evaporation have got the higher contributing factor for the incidence of YVMV. The D1 experiences prolonged favourable weather condition for YVMV incidence compared to D2. Conclusion: Twice foliar spray or soil application of boron reduced the severity of YVMV to a greater extent compared to no or once application among different concentrations @ 0.5% borax was the most suitable dose for Okra crop in the east and south-east coastal plain zone of Odisha.