Pineapple
Pineapple/ Settrot:
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C. O.: Ceratocystis paradoxa

Symptoms:

• Shortly after infection, the internal tissue of the seed piece turns red and eventually black.
• The black coloration results from the production of fungal spores within the seed piece.
• Nodes act as partial barriers to the spread of rotting, but with susceptible varieties, entire seed pieces may become colonized by the fungus.
• The disease severely retards bud germination, shoot development and early shoot vigor.
• Result in young plant-cane crops having a patchy, uneven appearance). When severe, the disease may reduce germination over large areas

Management :

• use of resistant cultivars is often the easiest, most economical method
• crop rotation or a fallow period between cane crops may prove to be of some benefit in reducing
• use of seedpieces containing at least three nodes increases the likelihood that buds closer to the center will germinate


Redrot
Red rot:
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C.O.: Colletotrichum falcatum
Glomerella tucumanensis


Symptoms :


• Red rot occurs in various parts of the cane plant but it is usually considered a stalk and a seed-piece disease. Its symptoms are highly variable depending upon the susceptibility of the sugarcane variety and the environment.
• Symptoms may not be readily apparent in the field, especially in the early stages of the disease. In the later stages of the disease, red rot may cause standing cane to "break down
• Diagnostic symptoms can best be observed by splitting the stalk lengthwise.
• The infected tissues have a dull red color interrupted by occasional whitish patches across the stalk. These white patches are specific to the disease and are of significance in distinguishing red rot from other stalk rots.
• Reddened vascular bundles may also pass through to the healthy tissues. In susceptible varieties the red color, sometimes along with some gray color, may be seen throughout the length of the stalk.
• The infection is largely confined to the internodes in resistant varieties.
• On the leaves, the pathogen may produce elongated red lesions on the midribs, reddish patches on the leaf sheaths, and, infrequently, small dark spots on the leaf blades.
• The lesions may eventually develop a straw color in the center.
• In seed pieces, the entire seed piece may become rotted and the internal tissues turn various shades of red, brown or gray.

Management:

• use of resistant varieties is the most effective method
• iIcidence of red rot can be reduced through good cultural practices, such as clearing fields of excessive trash and efficient drainage.
• The avoidance of planting susceptible cultivars during excessively cool and wet weather
• Regular roguing of diseased plants.


Whip smut
Smut:
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C. O.: Ustilago scitaminea

Symptoms:

• Primary spread of the disease is through infected setts and the secondary spread is through wind borne teliospore
• Stunting of infected stools, profuse sprouting of lateral shoots i.e., tillers, reduction in internodal length, formation of thin stalks and narrow erect leaves are certain symptoms of smut.
• Characteristic symptom is the production of long whip like structure from the terminal bud of the stalk, which is black in colour covered by thin silvery membrane. This silvery membrane ruptures releasing millions of reproductive spores of smut fungus, which are present in the form of powdery mass.
• Losses due to smut in sugarcane depend on various factors viz., primary or secondary infection, plant or ratoon crop that is affected and early or late infection and have been reported to range from 30 - 40% in plant crops and even up to 70% in ratoons. Sucrose content of infected cane is reduced to 3 - 7%.

Management:


• Healthy seed selection,
• Roguing of smut infected clumps
• Avoiding ratoons of plant
• Hot water treatment to sett
• Grow resistant varieties viz.Co 449, Co 527 and Co 6806


Wilt
Wilt:
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C. O.: Cephalosporium sacchari

Symptoms:

• Disease spreads through infected setts. The fungi gain entry mainly through injuries.
• Biotic stresses like nematode, root borer, termite, scales, mealy bugs etc and abiotic stresses like drought, water logging etc predispose the plants for wilt infection
• Moisture stress coupled with high temperature and low humidity reduces plant resistance to wilt.
• Typical wilt symptoms appear during monsoon and post monsoon periods.
• Affected plant appears wilted and conspicuously stunted. The crown leaves turn yellow, loose turgor and eventually withers.
• Wilt-affected canes loose their normal colour and are light in weight. The most characteristic symptom during the early stage of infection is the presence of diffused reddish brown patches on the internal tissue. Later canes become light and hallow and shrink.
• Disease reduces germination and in severe cases total cane yield losses occur due to drying up of shoots and wilting of the stalks.

Management:

• The disease is controlled by selecting seed setts from disease free areas.
• Alkaline soils may be avoided for growing the crop. The setts, selected from disease free stalk, should be dipped in organomercurial fungicide before planting.
• Dipping the setts in 40 ppm of boron or manganese, or spraying the plants with either of these minor elements reduces the disease intensity.
• The varieties Co-617 and B.P.-17 are more resistant than others; hence they should be used when growing crop in the wilt-sick soils.


Ratoonstunt
Ratoon Stunting :
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C. O.: Phytoplasma

Symptoms:


• Ratoon stunting disease has been considered as the most important cause for sugarcane varietal degeneration
• Primary spread of the disease is through infected setts.
• Also spreads through harvesting implements contaminated with the juice of diseased canes.
• Expression of disease is more under adverse conditions.
• Progressive yield decline takes place due to the disease. Ratoon crop suffers more damage due to RSD than the plant crop.
• Disease is known to reduce germination and yield
• Most characteristic symptom of the infected stalks is the presence of pin head like orange coloured dots of bacteria on the internal soft tissue in the nodal region.
• Other symptoms include stunted growth, thin stalks with short internodes, pale yellowish foliage and rapid tapering of the stem towards the top

Management:

• The disease spreads mainly through planting material, setts should be selected from healthy plants.
• Treating the seets in hot water at 500C for about 2 hours gives 100 per cent control and has become a regular practice in many countries.


Grassy Shoot
Grassy Shoot:
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• It is a mycoplasamal disease.
• Primary transmission of disease is through disease infected setts
• Profuse tillering with narrow chlorotic leaves giving a grass like appearance is characteristic symptom of GSD incidence
• Very few tillers of GSD infected plants develop into canes, which are thin and produce white shoots from the side buds.

Management:

• The disease is controlled by eradication of diseased parts as soon as symptoms are noticed
• Avoid selection of setts from diseased area
• pre-treating the healthy setts with hot water at 52°C for 1 hour before planting
• Treating them with hot air at 54°C for 8 hours and spraying twice a month with aphidicides.