Management of Orobanche in flue-cured tobacco in India
Orobanche (Orobanche cernua Loefl.) is a serious root parasite infesting tobacco roots in Northern Light Soil (NLS), Traditional and Mysore tobacco growing regions of India. The yield losses were ranging from 30-70% and plants show the symptoms of paleness with necrotic leaf tips and lamina.
The management practices in India include hand removal of Orobanche stems. Trials were conducted to identify better options for the control of Orobanche. Randomised block design experiments were conducted using amino acid as root dip and post emergence sprays of herbicides for the management of Orobanche in flue-cured Virginia (FCV) tobacco growing areas. The treatments include Methionine as seedling root dip, Imazethapyr (10% SL), paraquat dichloride (24sl) 0.5% and eco-friendly treatment of salt solution and vinegar (5%) as post emergence sprays at 55-70 days after planting. Seedling root dip for 15 minutes in methionine (3 mM solution) before planting has reduced the incidence of Orobanche by 73%. Imazethapyr (10% SL) at 0.15% spray concentration applied at 50-70 days after planting reduced the recurrence of Orobanche stem number by 79.2%. Growing gingelly with a seed rate of 7.5 kg/ha reduced the incidence of Orobanche by 81%. Paraquat dichloride (24sl) and vinegar (5%) + salt solution killed the Orobanche plant within 24 hrs of spray treatment.
The integrated Orobanche management approach includes: a) crop rotation with gingelly; b) seedling root dip with amino acid methionine; c) post emergence spray application of herbicides paraquat dichloride & imazethapyr; d) post emergence spray application of vinegar + salt solution.