Studies on Variability and Eco-friendly Management of Sugarcane Red Rot Disease Caused by Colletotrichum falcatum Went.
Loading...
Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Dr.RPCAU, Pusa
Abstract
Sugarcane is an economically important agro-industrial crop cultivated in
tropical as well as subtropical parts of the country. It is chief source of white sugar,
jaggery, khandsari and other bio products. The low yield and productivity of
sugarcane can be attributed to infection by numerous plant diseases. Among them, red
rot disease caused by Colletotrichum falcatum Went. is the most common and
dreaded disease of sugarcane.
The sugarcane plant exhibiting typical red rot symptoms were collected from
the various reserved areas of sugar factories in Bihar. A total of twenty seven isolates
of pathogen was obtained and they were studied for their cultural and morphological
characteristics. The various colour of colony such as white, whitish grey, greyish
white, ashy grey, light brown and pinkish white and colony margin either smooth or
irregular were observed. The various pigmentation on the reverse side of the plate viz.
creamish, light yellow, dark yellow, light pink and black were observed. The mycelia
of the isolates were either aerial or subaerial, sparse, scanty or abundant with flat,
slightly raised to fluffy texture. The average length of conidia varied from 19.87 to
31.47 μm and width varied from 3.74 to 4.72 μm. The pathogenic behaviour of the
isolates revealed that fourteen isolates were similar to Pathotype-1 (CF 08), six
isolates as Pathotype-2 (CF 07) and seven isolates behaved as Pathotype-3 (CF 01).
Amongst 48 genotypes/varieties evaluated against sugarcane red rot disease, 10
genotypes/varieties were graded as resistant, 26 as moderately resistant, 6 as
moderately susceptible and 6 as susceptible against the isolate CF 07. However, 8
genotypes/varieties showed resistant, 24 as moderately resistant, 8 as moderately
susceptible and 8 as susceptible reaction against CF 08 isolate. In vitro efficacy of
fungicide indicated that Carbendazim was most effective in inhibiting the mycelial
growth of the test fungus followed by Propiconazole while, Azoxystrobin was least
effective against all the three pathotypes. In vitro evaluation of botanicals revealed
that Neem leaf extracts proved most efficacious followed by Tulsi while, Bael was
least effective against all the three pathotypes of red rot pathogen. Amongst all the
intercrops evaluated with sugarcane under field condition for two consecutive
cropping seasons i.e. 2019-20 and 2020-21, sugarcane intercropped with garlic
showed outstanding results in both the cropping seasons followed by coriander while
lentil was most inferior among all the treatments in reducing red rot disease,
enhancing germination and yield attributes of sugarcane. Among all the fungicides,
botanicals and micronutrients evaluated under the field condition for two cropping
seasons i.e. 2020-21 and 2021-22, Sett treatment + drenching + spraying with
Carbendazim + Furrow application of Borax + Zinc sulphate proved most effective in
reducing red rot disease incidence and enhancing all other cane attributes. Although
botanicals were inferior in comparison to three used fungicidal treatments however,
botanicals were found comparatively superior to fungicides in terms of enhancing
micronutrients availability and soil quality. The botanicals positively favoured the
availability of soil organic carbon, availability of macronutrients (N, P and K) and
micronutrients (Fe, Mn and Cu) in the soil.
Based on the above findings, it may be concluded that a holistic combination
of various disease management approaches i.e. selection of resistant varieties for
planting, intercropping of sugarcane with suitable crops, use of fungicides, botanicals
as well as micronutrients would lead to long term sustainability and higher
profitability