STUDIES ON MOULDY CORE AND CORE ROT OF APPLE CAUSING PREHARVEST FRUIT DROP

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dc.contributor.advisorSHARMA, J.N.
dc.contributor.authorHANS, RAJ
dc.date.accessioned2017-02-16T07:02:11Z
dc.date.available2017-02-16T07:02:11Z
dc.date.issued2009
dc.description.abstractAbstract The present investigation entitled “Studies on mouldy core and core rot of apple causing preharvest fruit drop” was undertaken to study the occurrence and incidence of mouldy core and core rot of apple in Shimla district of Himachal Pradesh including isolation and identification, pathogenicity test, cultural characteristics, epidemiological studies in relation to disease initiation and spread of Alternaria alternata the major pathogen involved in mouldy core and core rot of apple. In vitro evaluation of different plant extracts, oils and biocontrol agents of fungal and bacterial origin was also undertaken in present investigation. In vitro and in vivo evaluation of systemic and non-systemic fungicides was undertaken to control the diseases in the field. Maximum incidence (17.70 %) of mouldy core and core rot was recorded at Kotkhai with on an average 16.2 per cent incidence of both these diseases in the surveyed areas of Shimla district. Alternaria alternata was found consistently associated with mouldy core and core rot causing preharvest fruit drop. Its pathogenicity was proved by standard methods and identity was confirmed from standard literature. The pathogen associated with the disease grew best on potato dextrose agar medium at 250C temperature and 6.5 pH. Potassium nitrate and maltose were best nitrogen and carbon sources supporting maximum growth of the Alternaria alternata. For germination of conidia of Alternaria alternata, 30°C temperature and 100 per cent relative humidity were found optimum under in vitro conditions. Among different weather parameters, cumulative rainfall was directly correlated with disease development during both 2008 and 2009 cropping seasons. Regression analysis further showed that the 91.00 per cent variation in preharvest fruit drop was due to mouldy core and core rot. Medium sized Starking Delicious apple fruits with open sinus/calyx tube and length : width ratio falling in 0.96 to 1.05 mm class showed maximum incidence of mouldy core and core rot in the field. Among different plant extracts and essential oils tested in vitro, mehandu (Dodonia viscosa) extract and cinnamon (Cinnamomum camphora) oil gave the maximum growth inhibition of Alternaria alternata. Among the biocontrol agents, Trichoderma hamatum exhibited the maximum inhibition. Under laboratory conditions, EBI fungicides difenoconazole and hexaconazole, and non-systemic fungicide iprodione + carbendazim gave maximum inhibition of mycelial growth as well as spore germination of Alternaria alternata. In the field, EBI fungicides (difenoconazole, hexaconazole and myclobutanil) and protectant (mancozeb flowable, dodine and captan) gave better disease control. Three sprays of difenoconazole sprayed at pink bud, full bloom and petal fall stages of apple provided 94 per cent control of mouldy core and core rot followed by sprays of mancozeb (at pink bud), difenoconazole (at full bloom) and hexaconazole (at petal fall) with 90 per cent disease control without hampering the fruit set.en_US
dc.identifier.other47108
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810001188
dc.keywordsapple , core rot ,mouldy core, diseases,managementen_US
dc.language.isoenen_US
dc.publisherUHF,NAUNI,SOLANen_US
dc.subPlant Pathologyen_US
dc.subjecteconomics, biological phenomena, resins, productivity, technological changes, exhibitions, developmental stages, marketing, biological development, selectionen_US
dc.themeapple , core rot ,mouldy core, diseases,managementen_US
dc.these.typeM.Scen_US
dc.titleSTUDIES ON MOULDY CORE AND CORE ROT OF APPLE CAUSING PREHARVEST FRUIT DROPen_US
dc.typeThesisen_US
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