Management of sesame phyllody disease in Assam, India

Four different insecticidal treatments along with a control were evaluated to manage the sesame phyllody disease in Assam, India. Seed treatment with imidacloprid 70% WG at 6 g/kg of seed plus foliar spray of thiamethoxam 25% WG at 2 g/10 l H₂O at 20, 35, 50 days after germination of sesame seed resulted in the lowest incidence of sesame phyllody disease (9.20% and 11.17%), lowest population of leafhopper Heshimonus phycitis (2.99 and 2.95 average insects in 5 sweeps of net), highest seed yield (5.41 and 5.34 q/ha) and highest benefit: cost (B:C) ratio (2.06 and 2.03) during 2019 and 2020 respectively. This was followed by seed treatment with imidacloprid 70% WG at 6 g/kg of seed plus foliar spray of imidacloprid 17.8% SL at 2 ml/10 l H₂O at 20, 35, 50 DAG resulting in disease incidence of 10.28% and 13.71%, leafhopper population of 3.85 and 4.20 per 5 sweeps of net, seed yield of 5.16 and 5.02 q/ha along with B:C ratio of 2.01 and 1.96 during 2019 and 2020 respectively. Highest disease incidence (39.33% and 38.82%), highest leafhopper population (6.10 and 6.49 average insects per 5 sweeps of net), lowest seed yield (3.29 and 2.91 q/ha) with considerably low B:C ratio (1.56 and 1.39) was observed in the control plots during 2019 and 2020 respectively. The sesame seeds produced in the insecticide treated plots resulted to be free from residues of imidacloprid and thiamethoxam. Considering the B:C ratio, seed treatment with imidacloprid 70% WG at 6 g/kg of seed plus foliar spray of thiamethoxam 25% WG at 2 g/10 l H₂O at 20, 35, 50 DAG can be effectively used to manage sesame phyllody disease.