Studies on Prevalence, Identification and Management of Alternaria blight (Alternaria spp.) of Cumin (Cuminum cyminum L.)
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Date
2022-08-03
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Agriculture University, Jodhpur
Abstract
Cumin (Cuminum cyminum L.) is an important seed spice crop, belonging to
family Apiaceae (Umbelliferae) under order Apiales. Cumin is believed to be
originated from Mediterranean and near Eastern regions of the globe. Cumin is
popularly used for flavouring food, herbal medicine and culinary for flavouring soups,
pickles and vegetables, for this reason it stands first position and popular all over the
world among seed spices. Seed and soil borne pathogens are the major constraints in
production of cumin, causing poor germination and early mortality of seedling.
Cumin crop is mainly affected by three fungal (wilt, blight & powdery mildew)
diseases. In the early stage of infection affected plants show minute, isolated whitish
necrotic areas which turn purple with age and later become brown and finally black.
Seed losses to the extent of 83% due to blight has been reported.
In the present investigation, during surveys of different location in Jodhpur
region intensity and incidence of Alterrnaria blight disease in Jodhpur district ranged
from 40.2 % to 60.16% and 42.83% to 70% respectivly. The highest disease intensity
and incidence was found in Bilara tehsil at 60.16% & 70% followed by Tinwari
(49.23 & 57.5%), Osian (48.86 & 58.8%), Phalodi (47.76 & 50%) and minimum
(40.2 & 42.83%) disease intensity & incidence was recorded in Lohawat tehsil. The
inter relationship between weather parameters and Alternaria blight revealed that
optimum temperature (15oC to 30oC), maximum R.H and clouds formation observed
significantly positive effect on Alternaria blight during year 2021-2022.
The freshly infected cumin plants exhibited typical blight symptoms were
collected from the farmer’s field and isolated by following standard tissue isolation
method and revealed the association of Alternaria spp. after studying the cultural and
morphological characters of the fungus and the pathogenicity was proved by
following Koch’s Postulates. The pure culture identified as Alternaria burnsii.
Thirty cumin germplasm were screened under natural field condition and none
of the germplasm showed highly resistant and resistant reactions. Three germplasm
were found as moderately resistant against Alternaria blight.
In the experiment on management of Alternaria blight the fungicides were
tested in vitro and found that tebuconazole 50% + trifloxystrobin 25% WG (75 WG)
inhibited the 100% mycelial growth at all the concentrations. However, under field
condition, pyraclostrobin 13.3% + epoxiconazole 5% SE @ 1.5 ml/lit (11.4%) and
resulted in increased seed yield with resulted in good B:C ratio (3.0) lowest disease
intensity.
Among the bio-inoculants tested in vitro in dual culture analysis Trichoderma
viride (71.36%) was found most efficient inhibiting the mycelial growth. In
conclusion it can be inferred that effective management of Alternaria blight can be
obtain through the judicious use of fungicides along with biocontrol agents.
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Yadav, Gopal Lal 2022. Studies on Prevalence, Identification and Management of Alternaria blight (Alternaria spp.) of Cumin (Cuminum cyminum L.). M.Sc. Thesis, Agriculture University, Jodhpur