Integrated management of sugar cane diseases
By M. Mithal Jiskani
CANE (Saccharum officinarum) is grown all over the
country as one of the important cash crops. Apart from
being the main source of sugar, the crop provides
essential ingredients for chipboard, paper, chemicals,
plastics, paints, synthetics, fibre, insecticides and
Harvesting, transporting and issues of sugar cane and
sugar prices as well as export and import of the
commodity are some of the typical technical issues,
which play a major role in the politics of our country.
But apart from these issues, cane diseases are the
hidden realities that result some time in 100 per cent
crop losses. Many farmers are totally unaware of these
diseases. The Ministry of Food, Agriculture and
Livestock (Minfal) has decided to bring over 1.0395
million hectares under sugar cane cultivation with an
aim to meet the domestic needs of sugar during the
current financial year. According to official source, a
bumper crop of sugar cane was harvested during the last
financial year by bringing about 1.03 million hectares
under sugar cane cultivation and producing 54.8 million
tons of the crop. The ministry has decided to increase
per hectare output of the crop by using quality seeds
and providing financial and technical assistance to the
growers. But how it could be possible to achieve the
target without proper knowledge of the causes,
identification and integrated management of diseases
damaging sugarcane crop?
Sugar cane suffers a lot from a number of diseases
caused by different organisms (fungi, bacteria, viruses
and nematodes) and factors such as environmental and
physiological disorders and nutritional deficiencies.
The diseases damage the crop from the very first stage
of growth and development till harvesting.
American phyto-pathological Society (APS) has reported
64 different diseases of sugar cane the world over,
which are: five bacterial and 40 fungal diseases, eight
are those which occur due to viruses and mycoplasma-like
organisms (MLO); three are caused by plant parasitic
nematodes and eight are listed as undetermined,
miscellaneous diseases and disorders. In our country, 37
diseases of sugarcane, caused by 55 different fungi,
bacteria, nematodes, viruses and nutritional deficiency
have been reported. According to another survey only
eight diseases have been recognised as major and four as
minor abnormalities, and 48 species of nematodes
associated with sugar cane have been pointed out. Among
them, five genera were observed dominant, but no
detailed studies have been carried out till now. Whereas
another surveyor described five important diseases, 15
were mentioned as insignificant and nematode problems
However, altogether 41 diseases of sugar cane have been
reported in the country.crop. It is essential for sugar
cane growers, environmental protection agencies and
pesticide-dealing personals, to diagnose the diseases
and adopt successful management of the crop.
Whip smut (Ustilago scitaminea): The affected canes
produce long, whip-like and coiled or curved, black
shoots, covered with a thin silvery membrane, containing
masses of chlamydospores of the fungus. The smutted
shoots may arise from the top of the cane or from
lateral buds. Later 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
Stem canker or wilting of canes (Cytospora sacchari):
The affected canes show dryness of leaves from top to
bottom. The cane stems are shriveled with considerable
reduction in quantity and quality of juice. Small,
black, dot like bodies of disease causing fungus may
develop on bud sheaths and hollow portions of canes.
Some times only a few internodes are affected, but whole
stool or only a few canes in a stool may be affected.
Red rot (Colletotrichum falcatum): The disease first
appears as red bright lesions on the mid rib of leaves
and shows itself as drooping and changing of colour of
upper leaves. Withering of leaves proceed from top to
bottom. Usually third or fourth leaf from the top is
affected and shows dryness at the tip. The pith becomes
red and later on brown. In severe cases, complete
destruction of the stools is brought about. When the
infected canes are spilt open they show reddened areas
and give out an alcoholic smell due to fermentation.
Leaf spot (Helminthosporium spp): The disease is
characterised on leaves as small lesions, which
gradually enlarge along the mid rib and assure dark red
to brown colour. In severe infection, leaves become dry
affecting photosynthesis. Pokkah boeng or distorted top
(Fusarium moniliforme): The disease appears in different
stages representing development of chlorotic areas at
the basal parts of the lower leaves, development of
irregular reddish specks or stripes and appearance of
top rot followed by total killing. Young leaves may also
show pronounced wrinkling, twisting and shortening,
depending upon the varieties and climatic conditions. In
tolerant varieties there may be recovery of growth, in
Rust (Puccinia melanocephala): Initially light green to
yellow coloured, small, elongated spots appear on the
lower leaf surface. These spots enlarge and turn orange
to reddish-brown lesions. The reddish spores come off
easily as a fine powder on touching the lesions.
Red stripe or top rot (Xanthomonas rubriieans):
Initially water-soaked yellowish stripes occur on
leaves, later on these become dark red. In severe
infection, lateral buds show reddening, terminal buds
and spindle leaves may die causing top rot, and the
vascular bundles exude foul smelling yellowish gum on
Mosaic virus: Mottling of young crown leaves show a
pattern of alternating dark and light green coloured
patches of varying size and run parallel to the midrib
Nutritional deficiency: Sugar cane is considered good
indicator plant for potassium deficiency, in which
necrotic spots develop on leaf blades, marginal necrosis
or leaf scorch also found, while terminal and lateral
buds show die back symptoms, confusing with red rot and
top rot diseases. Soils with low organic matter produces
chlorosis due to nitrogen deficiency, and the leaves
usually become red, especially along vein, in case of
Minor diseases: Other minor diseases of sugar cane are:
chlorotic streak virus, ratoon stunting, yellow spot and
genetic variegation of leaf and sheath.
Perpetuation and transmission: Smut, stem canker or
wilting of canes, red rot, leaf spot and red stripe or
top rot diseases are carried over from year to year by
ratooning or planting sets taken from smutted shoots of
cane. Soil-borne infection may also take place. Wind
disseminates all these diseases including rust, while
infected sets and aphids transmit mosaic virus, and
maize and sorghum are its alternate hosts. However, it
can not be asked how the pokkah boeng disease can
Disease management: Resistance is the most easy,
economical and less health hazardous precautionary and
control measure against all such diseases. Therefore,
available disease-resistant varieties should be planted.
BL-4 is resistant to red rot, rust and smut. Triton is
resistant to rust and susceptible to red rot and borers
(vectors of red rot). Co.L-54 is resistant to red rot
and susceptible to rust, smut and borers. BF-162 is
highly susceptible to red stripe and rust diseases.
• Most of the diseases causing pathogens survive from
season to season in the soil or on seed sets and other
crop debris in soil and build up to damaging levels with
repeated cropping (ratoon and continuous cultivation).
Therefore, 3-4 years suitable crop rotation with
non-host crops is recommended.
•Many of insect pests and pathogens are killed in direct
sun heating and drought; therefore, fallow lands must be
plowed at short intervals, with soil converting deep
ploughs and the planting should be done in healthy soil.
•Dry sowing of the crop should be carried out, where
smut is prevalent.
•The planting time sometimes favours or disfavours
multiplication of disease-inciting organisms. Therefore,
change in planting time is recommended in various cases.
For example, autumn planting should be avoided,
especially with reference to smut.
•Disease-free sets of eight-month-old sugarcane nursery
may be preferred for planting. Most of the diseases are
introduced into fields through infected seed sets;
therefore, efforts should be made to obtain disease-free
sets. Or seed-sets should be disinfected either in 0.1
per cent mercuric chloride or formalin solution for five
minutes followed by two hours covering under a moist
cloth. The other effective chemicals available in market
may also be used.
•Hot water treatment of sets at 52 degrees C for 18
minutes can help eliminate the internal infection of
smut causing fungi.
•Mostly weeds serve as alternate hosts or sources of
infection for pathogenic diseases. Therefore, effective
weed control practices should be adopted.
•The crop should be irrigated properly, because,
excessive or frequent irrigation as well as shortage of
irrigation favours the spread and development of many
pests and diseases.
•Proper use of fertilisers is also recommended, because,
heavy doses of nitrogenous fertilisers may maximise but
judicious use of potassic fertiliser minimises the
susceptibility of plants.
•Many pathogens survive in and on the plant debris or
pruned parts of plants, therefore phyto-sanitary
precautions including collection and burning of diseased
plant (or parts) from standing crop help minimise spread
of the disease. Just after harvesting, these should be
incorporated into the soil by ploughing or disking to
•Insects hit directly and are major source of
transmission of virus and other diseases. Therefore,
insects must be controlled through IPM.
•Monitoring or scouting allows for early detection of
all pests and diseases for timely implementation of
management practices. T therefore, the crop should be
monitored or scouted weekly for assessment of the
effectiveness of implemented management programmes.
•No doubt, pesticides are needed for effective
management of insect pests, diseases and weeds, but with
special reference to sugarcane diseases, no severe and
serious disease damages are recorded. Therefore, no need
of pesticide has been felt till now.
•Ratooning of the diseased crop should be discouraged.
Courtesy: The DAWN