Epidemiology, Variability and Management of Anthracnose of Sorghum [Sorghum bicolor (L.) Moench] Caused by Colletotrichum graminicola (Ces.) Wilson
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Date
2018
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MPUAT, Udaipur
Abstract
Epidemiology, Variability and Management of Anthracnose of Sorghum
[Sorghum bicolor (L.) Moench] Caused by Colletotrichum graminicola
(Ces.) Wilson
N. S. Tanwar Dr. R. N. Bunker The present investigations were undertaken to study epidemiology, variability and
management of anthracnose of sorghum caused by Colletotrichum graminicola (Ces.).
The studies were aimed at cultural, morphological characters and pathogenic variability
among the isolates of C. graminicola, epidemiological factors influencing disease
development, to assessment of losses and to develop integrated disease management
involving use of fungicides, botanical and host plant resistance.
Surveys of farmer’s fields during 2013-14 revealed that the disease was prevalent in
moderate to severe form in all the districts of Southern Rajasthan. Isolates of C.
graminicola recovered from various samples collected from Udaipur, Chittorgarh,
Bhilwara, Rajsamand and Kota (Rajasthan), Indore (Madhya Pradesh), Pantnagar
(Uttarakhand) and Hyderabad (Andhra Pradesh) showed variations in symptoms and also
in growth characteristics, colony diameter, extent of sporulation and the size of conidia,
seate and accervuli.
The isolates showed considerable variations in latent period, virulence and
aggressiveness across sorghum lines. The shortest (94.8 hrs) mean latent period was
recorded for the isolate Udr Cg-01 (Udaipur) and longest (107.3 hrs.) for Rjs Cg-04
(Rajsamand) across the eighteen sorghum lines. The isolate Udr Cg-01 (Udaipur) was the
* Research Scholar, Department of Plant Pathology, Rajasthan College of Agriculture, MPUAT, Udaipur
** Assistant Professor, Department of Plant Pathology, Rajasthan College of Agriculture, MPUAT, Udaipur
most virulent, as it caused highly susceptible (HS) reaction on five lines and susceptible (S)
reaction on six lines.
Environmental factors essentially affect intensity and spread of plant diseases and
thus, the knowledge concerning epidemiology can help in better management of the disease.
In 2014, maximum disease was observed with increasing order during 20 August to 9
September (standard week 34–36) with mean PDI (33.3-68.3) whereas in 2015, maximum
disease was observed with increasing order during 06 August to 26 August (standard week
32–34) with mean PDI (39.2, 51.3 and 58.2), respectively. Among the abiotic factors, the
maximum temperature, rain fall and relative humidity had a significant contribution in
increased per cent disease index.
Twenty-eight-days old sorghum plants observed as most susceptible stage for
infection of C. graminicola. The pathogen infected various hosts namely Zea mays (Maize),
Sorghum halepense (Kans), Pennisetum glaucum (Bajra), Eleusine indica (Indian goose
grass), Dactyloctenium aegyptum (Crowfoot grass), Cymbopogon citriodora (Lemon grass)
and Echinocola colonum (Barnyard grass) in cage house study.
The disease severity increased (44.5 to 80.8) with increased inoculum levels (1 x 104
to 1 x 106 conidia ml-1), and a significant reduction in (12.9 to 42.08 per cent) grain and
(10.1 to 27.3 per cent) fodder yields occurred at all the severity levels, as compared to the uninoculated
protected control plot.
Under field conditions, Dithane M-45, metalaxyl and neem oil (NF2) were more
effective when applied in integration as seed treatment or spray. The integration of
fungicides and botanical application resulted in (29.2 to 58.6%) in increased grain and
(19.1 to 26.1%) fodder yield, over individual application as well as the untreated control.
Out of 100 sorghum lines evaluated under inoculations of C. graminicola, 64 lines of
sorghum exhibited resistant reaction, twenty six showed moderate reactions, four lines
exhibited susceptible reaction and six lines exhibited highly susceptible reaction to the C.
graminicola in field. It would be therefore desirable to evaluate the promising materials
against various isolates of C. graminicola to find out the stable sources of resistance and
also adopt seed testing and seed treatment to avoid further spread of the new pathogen in
newer areas and manages virulence variability in C. graminicola.
Description
Epidemiology, Variability and Management of Anthracnose of Sorghum
Keywords
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Citation
Tanwar, N.S. and Bunker, R.N.