INVESTIGATION ON ASSOCIATION OF Ceratocystis fimbriata Ell. and Halst. AND Meloidogyne incognita (Kofoid and White) Chitwood IN CAUSING WILT OF POMEGRANATE AND IT’S MANAGEMENT
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Date
2018-07-13
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University of Horticultural Sciences, Bagalkot (COLLEGE OF HORTICULTURE, BAGALKOT)
Abstract
Pomegranate (Punica granatum L.), one of the important commercial horticulture crops of Karnataka, is highly threatened by the wilt complex caused by Ceratocystis fimbriata and Meloidogyne incognita. To know the incidence and severity of the disease, a survey was conducted during 2016-17 and 2017-18 in Bagalkot and Vijayapur districts of northern Karnataka. Among two districts, average per cent disease index of wilt was noticed maximum in Bagalkot (8.53%) than Vijayapura (7.15%). In Bagalkot district, average wilt disease incidence was maximum in Badami taluk (19.91%). In Vijayapura district average wilt disease incidence was maximum in Sindgi taluk (13.49%). The wilt incidence, root knot infestation and shot hole bore incidence were higher in orchards of 4-5 years old compared to orchards below 2-3 years. The Ceratocystis fimbriata was isolated from infected tissues using carrot baits. The pure culture was maintained on potato dextrose agar at 25±10C. The prevailing root knot nematode species on pomegranate was characterized based on the perineal pattern. Interaction study of C. fimbriata and M. incognita on pomegranate was carried out under pot culture, which revealed that simultaneous inoculation of C. fimbriata and M. incognita showed early and highest wilting symptoms and galls, followed by inoculation of C. fimbriata 15 days prior to inoculation of M. incognita. These two treatments adversely affected plant growth parameters viz., fresh and dry weights of roots, shots and root and shoot length. In vitro studies recorded that, non systemic fungicides viz., mancozeb 63% + carbendazim 12% at 0.025%, concentrations; systemic fungicides viz., hexaconazole and propiconazole at 0.025% concentrations and 3 isolates of bio agent Trichoderma spp, were effective against C. fimbriata. Phorate @ 0.01 g/ml and neem cake @ 0.1 g/ml were effective against M. incognita.
Pot culture studies revealed propiconazole (0.1%) and tebuconazole @ 0.1% were effective against C. fimbriata, while phorate @ 9 g/pot and neem cake @ 50 g/pot were effective against M. incognita. Under field conditions, propiconazole @ 0.2% + phorate @ 18 g/ plant and propiconazole @ 0.2% + neem cake @ 100 g/plant + T. harzianum @ 100 g/plant were found effective in controlling the disease complex with high fruit yield (19.70 and 17.55 kg) and net returns (` 7,40,423 and 6,10,701) compared to other treatments.