Identification and management of 16SrII-D phytoplasmas in cluster bean and sesame crops in the Haryana province of India

Little leaf, phyllody and witches’ broom symptoms with incidence of 8% to 20% were recorded in cluster bean, sesame and a weed (Phyllanthus niruri) in farmer's fields at Ranila and Begoa villages of Bhiwani district, Haryana, India during September-October 2017–2018. The phytoplasma presence was confirmed in symptomatic samples by phytoplasma-specific universal primer pairs nested PCR assays (P1/P7 and R16F2n/R2). Empoasca motti feeding in symptomatic cluster bean and sesame fields was also found positive for phytoplasma presence with the same nested PCR assays. Comparison of 16S rDNA sequence and virtual RFLP analysis of R16F2n/R16R2 primed sequences of cluster bean little leaf, sesame phyllody, P. niruri witches’ broom and leafhopper phytoplasmas indicated the presence of a ‘Ca. P. aurantifolia’-related strain classified in subgroup 16SrII-D. Spray of imidacloprid and thiamethoxam effectively controlled the leafhopper population and reduced the incidence of phytoplasma disease in the affected cluster bean and sesame fields.