Intensity of papaya ring spot disease in district Hyderabad Pakistan and its management using antiviral compounds
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Abstract
Papaya ring spot disease caused by Papaya ringspot virus (Genus: Potyvirus, Family: Potyviridae) is a major yield limiting factor of papaya in Pakistan. In severe attack of the disease crop can be lost completely. The aim of the study was to estimate prevalence of this destructive disease in district Hyderabad and to evaluate the effectiveness of Azaguanine and Ribavirin for managing the disease. During survey in Hyderabad, the incidence (%) and severity (score) of the disease was determined. Sap obtained from disease plants was mechanically inoculated on 30 days old test plants and induction of typical symptoms was noted. After induction of local lesions both chemicals at concentration of 100, 500, 1000 µM were applied with five replications. Non-significant difference among disease incidence (%) was recorded in Hyderabad (Df = 4, F = 0.49, P = 0.7435). Severity of the disease was significantly varying in the surveyed fields in Hyderabad (Df = 4, F= 1.59, P = 0.1843). Mechanically inoculated plants showed 100±0 % incidence and 2.2±0.5 severity score. Among various tested concentrations of Azaguanine and Ribavirin, only 1000 µM significantly decreased 40 ± 3.3 % incidence and 0.4 ± 0.33 severity of the disease. It is concluded that disease is prevailing in Hyderabad and application of Azaguanine and Ribavirin at 1000 µM could reduce the disease. Furthermore, it is recommended at antiviral compounds shall be included in disease management strategy and additional studies shall be undertaken to address the mechanism of the antiviral compounds to control the disease.
Keywords: Azaguanine; Chemotherapy; Papaya; Papaya ring spot disease; Papaya ringspot virus; Ribavirin