Occurrence and detection of papaya ringspot virus (PRSV) type P on cucurbits in Maharashtra.

摘要

Cucurbits and papaya were surveyed in commercial papaya growing locations of Maharashtra state to know the incidence of PRSV type P and access their role in spread of the virus among themselves and to papaya orchards. Samples of 14 cucurbits and papaya were collected for diagnosis. Two hundred symptomatic, 54 symptomless cucurbits and 43 symptomatic and four symptomless papaya samples were collected. They were back inoculated on papaya by mechanical transmission and diagnosed by DAS ELISA using antiserum against PRSV type P. Cucurbits and papaya had severe virus symptoms of mosaic chlorosis, mottling and leaf distortion and in papaya shoestrings, ringspots on leaf and fruits were noticed during survey. Symptomatic and symptomless cucurbits of all the 14 types succeeded sap transmission except few samples. All symptomatic papaya samples were positive for mechanical sap transmission and two failed from symptomless. In serodiagnostic test, all symptomatic 14 cucurbits (98%) except four samples were found positive for presence of PRSV type P and out of symptomless more than 68% of the samples were positive. Papaya samples except one including symptomatic and symptomeless were positive (98%). The results of both the diagnostic tests show that cucurbits often succumb to infection by PRSV type P. Hence, they can act as alternate host for survival of virus in absence of papaya. It is better managed before spread, to cultivate cucurbit and papayas away from each other rather as intercrop or on farm bunds of papaya. The practice helps in management of virus in both cucurbits and papaya.