Biological properties, transmission, serological characterization and varietal susceptibility of an isolate of Papaya leaf curl virus affecting papaya crops in Eastern Uttar Pradesh, India

Abstract

Papaya leaf curl disease (PLCD) was recorded with 5–35% incidence at six districts of Eastern Uttar Pradesh during survey. The characteristic symptoms observed were severe downward leaf curling, swelling of veins, twisting and reduction of petioles, inverted leaf bowls and stunted growth of the entire plant which bore only few small and distorted fruit. The virus isolate was identified as Papaya leaf curl virus (PaLCuV).The PaLCuV isolate was successfully transmitted by whitefly (Bemisia tabaci) but not by mechanical (sap) transmission on Carica papaya plants. Plants could be proved efficiently from infected to healthy C. papaya, Capsicum annuum, Lycopersicon esculentum, Nicotiana tabacum, Crotalaria juncea, Ageratum conyzoides, Zinnia elegans, Datura stramonium and Petunia hybrida. Symptomatic samples of these plants were tested with polyclonal antiserum of Tomato leaf curl New Delhi virus by DAC-ELISA test showed the positive relationship of the samples with geminivirus. On the basis of symptomatology, whitefly transmission, host range studies and serological relationship, the isolate was identified as whitefly transmitted geminivirus. To identify potential varietal resistances source to PaLCuV, five cultivars of C. papaya were tested against PaLCuV using whitefly insects to transmit the infection. Results revealed that two cultivars (Washington and Ranchi Dwarf) were found to be moderately resistant.