EPIDEMIOLOGY AND MANAGEMENT OF FIG RUST CAUSED BY Cerotelium fici (Cast.) Arth.
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Date
2018-09
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University of Horticultural Sciences, Bagalkot
Abstract
The present research work on “Epidemiology and management of fig rust
caused by Cerotelium fici (Cast.) Arth.” was carried out at Department of Plant
Pathology, College of Horticulture, Bagalkot and in vivo studies at Fruit orchard,
UHS, Bagalkot and Horticulture Research and Extension Centre, Vijayapura
(Tidagundi) during 2017-2018.
The symptoms of fig rust was more pronounced on the leaves as brownish
angular spots on the adaxial surface and uredosori on the corresponding abaxial
surface of the leaf. The severity of the disease leads to the defoliation. The survey
carried out in the three districts of Northern Karnataka revealed that the highest
Percent Disease Index (PDI) was recorded in Ballary (66.93) and lowest in Bagalkot
district (51.46). The in vitro studies on uredospore germination revealed that, 2.5 per
cent sucrose, 25˚ C temperature and 100 per cent relative humidity favoured the
maximum germination of uredospores.
Among the weather parameters correlated, morning relative humidity (%) and
minimum temperature (˚C) had maximum influence on the disease development. In
vivo screening of varieties viz., Ballary, Conadriya, Dienna, Dinakar, Excel and Poona
showed that none of the varieties were found to be resistant to rust disease. The results
of analysis of bio chemical parameters showed that total sugars, reducing sugars, non
reducing sugars, total protein and total phenol content in the leaves were increased
due to the infection, whereas the chlorophyll content was decreased. The wax content,
a pre existing defense component was highest in the upper leaves which were immune
to the disease.
In vitro efficacy of fungicides, biorationals and bioagents indicated that
fungicides viz., propiconazole, carbendazim, difenconazole, tebuconazole, mancozeb
and trifloxystrobin+tebuconazole were found highly effective in inhibiting the
uredospore germination. Out of the different biorationals tested neem oil, safflower
oil, amrut pani, ginger rhizome extract, coconut oil and garlic bulb extract effectively
inhibited the uredospore germination. Among the bioagents viz., Bacillus. subtilis,
Pseudomonas. fluoroscens and Lecanicillium lecanii, completely inhibited the
uredospore germination.
In vivo (field) evaluation studies indicated that among biorationals, ginger
rhizome extract @ 15% was more effective in reducing the rust disease followed by
neem oil @ 5% and garlic bulb extract @ 15%. Among the different fungicides
tested, tebuconazole at 0.1 % propiconazole at 0.1 % and mancozeb at 0.25 % were
recorded the least PDI of 31.85, 35.06, 35.56 and highest BC ratio of 1:3.94, 1:3.80,
1:3.47 respectively.