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Subject: Plant Pathology × Author: Dhkal, Manmohan × Start date: 2010 × Thesis Type: Ph.D ×
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    Identification, characterization and management of major virus(es) associated with cucurbits in Punjab
    (Punjab Agricultural University, Ludhiana, 2018) Dhkal, Manmohan; Sharma, . Abhishek
    Viral disease was reported to be major constraint in the cucurbits cultivation under Punjab conditions. Disease survey conducted during February-August 2017 and 2018 in different cucurbits growing areas of Punjab revealed maximum viral disease incidence in district Pathankot (100%) during 2017 and Ludhiana (36.5%) during 2018. During survey blistering, yellows, leaf curl, mosaic, puckering and necrosis were observed as common viral symptoms on cucurbits. Among these, yellows and leaf curl were most prevalent symptoms on cucurbits in different districts of Punjab, whereas watermelon showed necrotic symptoms. Musk melon samples with yellows and leaf curl symptoms showed seronegative reaction against antisera of commonly occurring viruses and was found positive in PCR for whitefly transmitted begomovirus infection. Musk melon and tinda were identified as new host of begomovirus in India. Tomato leaf curl New Delhi virus (ToLNDV), Tomato leaf curl Palampur virus (ToLCPMV) and Seena leaf curl virus were characterized from musk melon showing yellows and leaf curl symptoms. ToLNDV infection was found to be associated with tinda and cucumber causing yellows and leaf curl symptoms. In watermelon, Groundnut bud necrosis virus (GBNV) was serologically detected with samples showing necrosis symptoms. Among different methods of transmission ToLCPMV associated with yellows and leaf curl symptoms was found to be transmitted only by whitefly, whereas one percent seed transmission of necrosis symptoms caused by GBNV was observed in watermelon. Out of 75 melon accessions SM/IC-267375 and WM-11 showed high resistance response against ToLCPMV in artificial screening as no symptom observed even after 45 days of sowing as compared to susceptible checks. Three watermelon accessions viz., WM-6-2-2-1-1-2, WM-36 and WM-829833 produced mild necrotic symptom during natural screening. Among different natural products used for management of viral disease in musk melon, buttermilk was found to be highly effective at 20% concentration with least per cent disease incidence (50.8%) as compared to 10 % (64.2 %) and 5 % (71.1%) concentrations. Besides buttermilk, kaolin was also found to be effective in the management of viral diseases of musk melon. Among different dates of sowing least incidence of viral disease was observed on late sown or transplanted musk melon crop 15 March (38.96%) followed by the 5 March (46.7%) sown crop. Among different methods of planting, tray transplanted musk melon crop showed less incidence (48.3%) compared to directly sown crop (50.4%) whereas, normally transplanted crop showed maximum disease incidence of 55.7 per cent.