sugarcane diseases

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SUGARCANE DISEASES

• BY
• JIMI PATEL
• Mo.No9924474599

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INTRODUCTION

• Sugarcane is not only cash crop for the growers,
  but it is main source of white crystal sugar. It
  also provides grower with a very good substitute
  of sugar as gur and khandsari (brown sugar).
• Sugarcane tops serve as fodder for cattle,
  baggage and leaf trashes as fuel, stubble and
  roots as organic manure and crop residues as
  mulch and compost.
• It may also be kept in mind that sugarcane leaves
  are used as substrate for the artificial
  cultivation of edible mushrooms.

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• There are many constrain, including the heavy
  losses, caused by a number of diseases to the
  sugarcane crop.
• More than 50 diseases are reported in sugarcane,
  fungi, bacteria, viruses and nematodes cause the
  most destructive diseases.
• These all diseases are injurious in some areas,
  in some years and on some plant parts.
• However, the causes, symptoms, transmission,
  perpetuation and control measures of different
  most important diseases of sugarcane are given as
  bellow.

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WHIP SMUT (Ustilago scitaminea)

• Symptoms
• The affected canes produce long, black whip-like
  and coiled or curved shoots, which are covered
  with a thin silvery membrane, containing masses
  of chlamydospores of the fungus.

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• The smutted shoots may arise from the top of the
  cane or from lateral buds. Later on that membrane
  ruptures and releases a multitude of spores,
  which contaminate soil and the standing crop.
• In certain cases, the infected plants remain
  stunted in growth with increased tillering of
  little value. The diseased plants are unfit for
  use.

• Perpetuation
• The disease is carried over from year to year by
  ratooning or planting sets taken from smutted
  shoots of cane. Soil borne infection may also
  takes place, while wind disseminates disease.

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Control Following measures are suggested for
prevention as well as control of the disease
1) Sets from smutted canes should not be used
for planting. 2) Seed-sets should be disinfected
either in 0.1 mercuric chloride or formaline
solution for 5 minutes followed by 2 hours
covering under a moist cloth. The other effective
chemicals available in market may also be
used. 3) Hot water treatment of sets at 52C for
18 minutes can help eliminate the internal
infection. 4) Smutted plants should be rouged out
and burnt before the bursting of the spores. 5)
Ratooning of the diseases crop should be
discoursed. 6)Use of resistant varieties should
be encouraged. 7) Planting should be done in
healthy soil. 8) Autumn planting of sugarcane
should be avoided.
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Rred Rot (Colletotrichum falcatum)

• Symptoms
• The disease first appears as red bright lesions
  on mid rib of leaves and shows itself as drooping
  and changing of colour of upper leaves.

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• Withering of the leaves proceeds downwards.
  Usually third or the fourth leaf from the top is
  affected and shows drying at the tip.
• The pith becomes red and later on brown. In
  sever cases complete destruction of the stools is
  brought about.
• Perpetuation
• The disease is perpetuated from year to year by
  planting sets from infected canes and also
  through the fungus that remains viable on
  diseased canes lying in the field or ratooning of
  the crop.
• Control
• Non ratooning and use of resistant varieties are
  recommended. Disinfecting of sets with effective
  and easily available chemicals.

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SUGARCANE MOSAIC VIRUS (SCMV, Potyvirus group)

• Symptoms
• Mottling of young crown leaves showing a definite
  pattern of alternating dark and light green
  coloured patches of varying size and run parallel
  to the midrib of leaf.

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Transmission Transmitted through mosaic
infected sets and an aphid. Alternate hosts
Maize and sorghum. Control Planting virus
free sets and avoid ratooning of diseased crop.
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GRASSY SHOOT DISEASE

• Symptoms
• This disease is characterized by the production
  of numerous small and thin tillers having narrow
  leaves with or without albinism.

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• Diseased plants exhibit varying degrees of loss
  of chlorophyll, ranging from total green to
  white. Premature excessive tillering gives a
  crowded appearance like grass to the clump.
• The root system of the affected plant reduced
  and plants are usually reduced in height (stunted
  growth). Affected clumps hardly produce one or
  two weak canes.
• In some cases, there is also formation of aerial
  roots at the lower nodes.

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Transmission

• The grassy shoot disease is primarily
  transmitted through the diseased seed material
  and perpetuated through ratooning. This disease
  is also transmitted by a) mechanically by Cutting
  knife, b) Insects (aphids) and c) Dodder (root
  parasite).

Control
Adopting one or more of the following measures
can minimize the disease incidence. 1)Use of
healthy diseased free planting material collected
from seed nursery for planting. 2) Roguing of
affected stools and destruction Mass
eradication may help consistent reduction in
inoculum in the area.
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3) Head therapy seed/planting material should be
treated with hot water (50oC for 120 Min.) or
moist hot air (54oC hr, 2½ hrs.) that eliminates
the Pathogen from diseased seed materials.
Ratooning of affected crop must be avoided. Crop
rotation may be employed to reduce inoculum in
the field. 4) Control of insect pests.
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Reference

• Ahmad, I. 1988. Fungal Diseases of Sugarcane. In
  Plant Disease Diagnosis Manual, Vol.2. CDRI,
  NARC, PARC. Islamabad.
• 2. Bhatti, I. M. and A. H. Soomro. 1996.
  Agricultural inputs and field crop production in
  Sindh. Agricultural Research Sindh, Hyderabad.
• 3. Bhatti, I. M. and M. M. Jiskani. 1996. Modern
  Agricultural Guide. Agricultural Research Sindh,
  Hyderabad.
• 4. Hafiz, A. 1986. Plant Diseases. PARC,
  Islamabad.

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