Studies on Alternaria Leaf Blight [Alternaria alternata (Fr.) Keissler] of Carrot (Daucus carota L.) and its Management
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Agriculture University, Jodhpur
Abstract
Carrot (Daucus carota L.), is most important vegetables root crop with huge
medicinal, nutritional and health value. Its belongs to Apiaceae family, are cultivated
worldwide. Its originated from Afghanistan is the main centre of origin. The carrot
suffers from several diseases among those Alternaria leaf blight is one of the most
horrible diseases are causing considerable quantities and qualitative losses in carrot.
A survey conducted for Alternaria leaf blight disease incidence in different
tehsils of Jodhpur district of Rajasthan showed that Tinwari, the maximum disease
incidence was recorded 24.02% followed by Osian (22.66%), Lohawat (18.17%),
Bawadi (13.84%). However, minimum disease incidence was recorded in Balesar
Tehsil (11.74%).
The freshly infected Carrot plant showing typical characteristic symptoms
of leaf blight disease were collected from farmer’s field and pathogen was isolated by
standard tissue isolation method and revealed the association of Alternaria sp. after
studying the cultural and morphological characters of the fungus and the
pathogenicity was proved by following Koch’s Postulates. The pure culture obtained
was sent for identification of Indian Type Culture Collection (I.T.C.C.), I.A.R.I., New
Delhi – 110 012 and was identified as Alternaria alternata (I.D. No. 11,480.21).
Ten carrot cultivars were screened under cage house condition and none of
the cultivars showed highly resistant and resistant reactions.
The fungicides were tested in vitro condition and found difenoconazole
25% inhibited the 100% mycelial growth at all the concentrations. When applied as
foliar application under cage house condition, difenoconazole 25EC at 0.25 ml/lit
(11.17%) was observed lowest disease incidence.
The phytoextracts, the garlic extract (68.33% & 80%) was observed to be
most effective inhibiting the mycelial growth at 5% and 10% concentrations,
respectively under in vitro condition against Alternaria altarnata.
Among the bio-inoculants Trichoderma viride (77.13%) was found most
efficient inhibiting the mycelial growth.
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Yadav Pooja 2021. Studies on Alternaria Leaf Blight [Alternaria alternata (Fr.) Keissler] of Carrot (Daucus carota L.) and its Management. M.Sc. thesis, College of Agriculture, Agriculture University, Jodhpur.