RED ROT OF SUGARCANE - Biology Ease

The red rot is a very known disease in sugarcane.
Sugarcane is a major agricultural crop worldwide. India is the largest consumer and the second-largest producer of sugar and the production of sugarcane plays a vital role. But diseases affecting sugarcane are a major concern for the low yield.
It is also known as the cancer of sugarcane.
It is caused by Colletotrichum falcatum Went.
It was recognised as a disease in Java by Went in 1893

Organism Involved

Red rot of sugarcane is caused by Colletotrichum falcatum Went

Systematic Position

Division: Eumycota

Subdivision: Deuteromycotina
Class: Coelomycetes
Order: Melanconiales
Family: Melanconiaceae
Genus: Colletotrichum
Species: falcatum

The common name of the disease is called Red Smut
C. falcatum is a facultative saprophyte.
It is a toxic producing fungi.
It’s sexual stage is known as Glomerella. tucumanensis is responsible for the survival of the fungus on decaying leaves and formation of new virulent pathological diseases.

Distribution

The major sugarcane producing countries are Brazil, India, United States of America , Australia, Thailand, Pakistan, China and Mexico,

Mode of Infection

The pathogen mainly infects canes through nodes and the main portal of entry are leaf scar, growth ring, root primordia and buds.
The disease attacks the sugarcane at the stalks, stubble rhizomes, and leaf midrib. It may even extend to leaf-blade and leaf-sheath tissues and is capable of infecting sugarcane roots.

Symptoms of Red Rot Of Sugarcane

Red rot can only be observed when it has been completely rotted in the interior and lose its natural bright colour and become dull.
Plants can be seen yellowing, shrivelling, and dying of the upper leaves.
The disease can be recognized by the longitudinal reddening of the normally white or
yellowish-white internal tissues of the internode
The lesions on the leaf midribs can be seen as dark reddish areas which may elongate and reach the entire leaf.
The young lesions are blood red in colour with darker margins.
The centers start fading and become straw-coloured with age, and when fructification of the fungus begins, the lesions are covered with black powdery masses of conidia.

Favourable conditions for the cause of the disease

It was considered that bad cultivation and poor drainage favour the cause of the disease
Environmental conditions in subtropical countries favour the disease.
Mean temperature range of 29.4 to 31°C
High atmospheric humidity

Losses Caused

The disease causes a stiff drop by reducing the crop stands and by reducing the sucrose content of the cane juice.
Additional to the sucrose reduction in internodes, the joints above the diseased positions were also affected.
Decreased juice extraction, percentage of solids and sucrose in the juice, purity and chemical changes were observed.

Disease Control

The control of the diseases depends upon weather conditions, genotypes, presence of virulent
pathogen and time for disease development.
It is impossible to control the disease once it appears on the field.
The direct focus can be in prophylactic measures to reduce pathogen build up in the field
Integrated Disease Management (IDM) can be followed.
Resistance varieties can be grown which is an efficient alternative against such huge losses.
Good cultural practices, using disease-free planting materials, physical, biologic and chemical control may aid to the control of diseases
Sustainable alternative including Bio-control agents can be used for the control.

References