Use of Agro-Insecticide, Plant Extracts and Resistance Inducers to Manage Yellow Vein Mosaic of Okra

Production of okra is under threat due to certain biotic and abiotic factors. Okra yellow vein mosaic virus (OYVMV) is a devastating disease of okra, caused by monopartite and bipartite begomovirus and transmitted by whiteflies (Bemisia tabaci Gen.). Yield loss due to this virus is quite high, up to 80-94 percent is reported under heavy infection. The efficacy of Malathion with botanicals and resistance inducers were tested against OYVMV in the field conditions for the effective management of the disease. The result revealed that among all the treatments malathion 50 EC (2 ml/litre) in combination with sarpagandha leaves extract (10%) had recorded the lowest terminal per cent disease index (PDI) (15.55%) during all the observation periods as compared to untreated check plot (71.68%). The fruit yield was also recorded highest (3833.20 kg/ha) in this treatment as compared to control (1811.15 kg/ha) and other treatments. For the evaluation of resistance inducers, the seeds were soaked in salicylic acid with concentrations of 50, 100 and 150 mg/litre water and Trichoderma viride @ 5 g/litre water at the time of sowing and later sprayed with the same doses at 15 days interval. Amongst different treatments, salicylic acid @ 150 mg/litre as seed priming and spray @ 150 mg/litre water recorded significantly less terminal PDI (28.89%) as well as the highest fruit yield as compared to other treatments and untreated check plot (73.33%). The treatment with bioagent Trichoderma viride @ 5 g/litre as seed priming and spray @ 5 g/litre water also effective in reducing the disease severity and increasing fruit yield significantly as compared to control.