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Clcuv de
facto and the life blood of Pakistan Economy
Mohammad Ali
Khaskheli Sanghar
Cotton is a major
world fiber crop. It is grown under a very broad range
of climates, soils and cultural practices. In Pakistan
it was grown on approximately 3.0 million hectares in
2003-04.
 Prior
to the introduction of man-made artificial fibers, it
was only the raw material from which human clothing and
other necessary textiles were manufactured. It produced
about 13.761 million bales of lint (PCGA report by
January 2005) and 780 kg of lint per hectare. Cotton
provides raw material to more than 337 textile mills,
1500 ginning factories and 5000 oil mills. Approximately
65 per cent of Pakistan's annual export income comes
from textile sector. Similarly other industries, such as
pharmaceutical, soap, chemical and feed industries also
rely on cotton by-products. Besides this, cotton is an
occupation of 1.5 million farming families and provides
job to 50-54 per cent of labour force. Therefore cotton
is known as the life blood of Pakistan economy.
Pakistan's consumption of cotton for the year 2003-04
was 9.6 million bales (of 480 lbs), whereas the
production was 8.2 million bales (of 480 lbs), this
indicates that we are still getting low yield. The
average per acre yield of our country is about 256 kg
per hectare, whereas our local varieties have a
potential to produce about 910 kg per hectare. So to
achieve this target potential yield, the cotton growers
should have to come up with modern agricultural
practices, especially crop protection and secure storage
techniques for maintaining the quantity and quality of
yield as well.
No doubt the grower's aims to ensure the maximum yield
with minimal adverse impacts, but there are several
factors which cause their economically unacceptable
damage. Unfortunately in our farming systems,
uncontrolled insect pests, diseases and weeds reduce
yields at harvest by 30-50 per cent and around 20-25 per
cent during storage.
Among yield decreasing factors, at present, the plant
diseases are the major concerns. Generally a heavy
disease infestation may cause crop losses by 30-50 per
cent, but under some specific conditions 100 per cent
losses are also observed.
Cotton Leaf Curl Virus
Since last two decades Pakistan economy is facing the
similar disastrous threat in the form of a cotton
disease known as cotton leaf curl virus (CLCuV). CLCuV
gives the sleepless nights to the cotton growers. Due to
its devastating effects, growers plowed thousands of
acres of standing cotton crop. Thus increasing graph of
cotton production of Pakistan greatly declined.
The fatal CLCuV, a viral disease of cotton, was first
recognized in 1912 in Nigeria with the common symptoms
of small vein thickening and upward curling leaves.
Later on it was reported from Tanzania in 1926 and from
Sudan in 1934.
In Pakistan, It was first reported in Multan (Punjab) in
1967. This disease was again re-emerged in 1988 in
Multan in Mauza Balail, where some foreigners were
working on an insecticide project. Initially only 150
acres were reported to be affected area, but in next
year this disease was spread to about 500 acres. The
serious notice was taken only in 1991 when a large area
about 35000 acres was reported to be affected, and a
huge yield losses occurred after a record crop (12.8
million bales) in 1991-92 and decreased to 8-9 million
bales per year in the next two years. In Punjab over an
area of 6 million acres, the crop yield was dropped from
343 kg per acre to 199-232 kg per acre. The total loss
due to this disease for three years (1992-93 to 1994-95)
was estimated about three million bales valued at rupees
30 billion.
This disease again appeared in the form of “burewala
virus” in burewala of Vehari district of Punjab in
2001-2002. The virus had 92 per cent same
characteristics as that of scientifically called
'giminivirus'. Almost all cotton varieties, including
those claimed as CLCuV-resistant also came under the
CLCuV attack. Hot spots of the CLCuV above varying
degrees of economic injury level were found in almost
all the cotton districts of the Punjab, especially
Vehari, Rahim Yar Khan, Dera Ghazi Khan, Bahawalpur,
Multan, Lodhran, Muzaffargarh and Layyah districts. As a
result to curb the problem, Punjab Government has put a
ban on cultivation any CLCuV-susceptible variety in
Punjab including NIAB-78, which is the most popular and
most stable cotton variety giving excellent performance.
In Sindh, this disease was first reported in 1996 at
Obauro (District Ghotki) and khairpur District.
Afterwards it was expanded to some areas of Nawabshah
and Hyderabad districts. In the year 2002, the total
arera affected by CLCuV was reported to be 10-15% in
northern Sindh. Now it is reached up to almost all
cotton growing districts, though with a minor intensity,
but it is still a major threat to our economy.
Causes and Symptoms
This is a viral disease, and the virus causing the
disease belongs to Gemini group. Generally there are 21
viruses are known which are associated with cotton
(Gossypium hirsutum). They are namely Abutilon Mosaic
Virus, Acromania, African Cotton Mosaic, Cotton
Anthocyanosis Virus, Cotton Blue Disease virus, Cotton
Leaf Crinkle, Cotton Leaf Crumple Virus (CLCrV), Cotton
Leaf Curl Virus (CLCuV),Cotton Leaf Mottle, Cotton Leaf
Roll virus, Cotton (common) Yellow Mosaic, Cotton Yellow
Vein (CYV)/(Texas Vein-clearing), Flavescence ,Flower
virescence (phyllody), Indian Leaf Crumple ,Infectious
Variegation, Murcha vermelhao/purple wilt, Stenosis
(small leaf),Terminal Stunt ,Tobacco Streak and Viral
Wilt.
The prominent symptoms of CLCuV are stunted crop growth
with small and dark green thick coriaceous leaves which
are curling upward or downward along with the thickening
of mid rib. In a severe attack, a small cup shaped
leaf-like structure, called “enation” is developed on
the back of leaves. No or small bolls formation is
occurred which failed to open.
Besides CLCuV, a minor infestation of cotton leaf
crumple virus (CLCrV) disease is also observed in
Pakistan. This disease was first reported in the
irrigated desert southwest in 1950.
CLCrV symptoms are distinguishable from CLCuV symptoms
in that infected leaves curl downward accompanied by
interveinal hypertrophy and foliar mosaic.
Both CLCuV and CLCrV are whitefly (Bemisia
tabaci)-transmitted and belong to the subgroup III
geminiviruses. However, little information is available
on the relationship of these two viruses with each other
and with other subgroup III geminiviruses.
Position of Cotton varieties
The quality seed is vehicle of technology through its
genetic composition and heads to successful production
across the agro-ecological condition. Availability of
quality seed of crop varieties continues to be a problem
of major concern for Pakistan agriculture.
There had been a long series of cotton varieties
released from various cotton research institutions, but
none of these could find acceptance with the cotton
growers. Only the NIAB-78, which occupies approximately
80% of the cotton area, due to its stability and high
yield potential since its year of release in 1982,
happens to be the cotton variety most acceptable to the
farmers and suits the farming system of the country.
Pakistan, therefore, revolves around only one variety
i.e. NIAB-78. However, it is not resistant to the cotton
leaf curl virus (CLCuV). Due to its susceptibility to
CLCuV, Punjab Government has put a ban on its
cultivation.
Though various agricultural research institutes have
developed more than 50 registered cotton varieties up to
2003, but most of them are susceptible to CLCuV and some
are not available in such a quantity to meet the home
demand.
Recently some varieties which are developed within a
very short period and are claimed as CLCuV resistant,
but it is pertinent to note that a variety CIM-473
remarked as atop for being CLCuV-resistant but,
according to a report of the directorate of pest warning
and quality control of pesticides, the variety was under
CLCuV attack in most of the cotton belt, including
Multan, Khanewal, Vehari, Pakpattan. Other preferred
cotton varieties like CIM-446, FH-900 and FH-901 are
also reported with the same problem. Currently, there
seems to be no variety fully resistant to CLCuV disease,
consequently CLCuV-resistant varieties need to be
evolved which are otherwise similar in characteristics,
and preferably high yielding than the most popular
variety i.e. NIAB-78
MANAGEMENT OPTIONS
1-The continued use of CLCuV-susceptible varieties
without any program of their replacement constitutes a
major risk for cotton production in Pakistan. So a
premier focus should be given to eliminate the CLCuV
disease and a well-planned program of evolution and
introduction of CLCuV-resistant varieties of desired
characteristics must be in place to gradually replace
the existing CLCuV-susceptible varieties. This is only
the sole and the most promising and least expensive
method of disease suppression.
2- The federal government has allocated a sum of Rs
149.1 million for the development of CLCuV resistant
cotton varieties. For this task four federal research
institutions; Central Cotton Research Institute (CCRI)
Multan, CCRI Sakrand (Sindh), Nuclear Institute of
Agriculture and Biology (NIAB) Faisalabad and Nuclear
Institute of Biology and Genetic Engineering (NIBGE)
Faisalabad have been selected. But a period of some
twelve long years is required to evolve a new cotton
variety after cross-breeding repeatedly. Presently,
there is no variety which is fully resistant to this
disease, therefore government needs to be full attentive
and to pay an urgent attention for the preventive
measures against this disease for the next crop.
3- In the absence of CLCuV-resistant varieties, the
immediate solution for eliminating or reducing the
menace of disease lies in the adoption of modern
agricultural techniques. Destruction of host plants (all
weeds especially broadleaved and stub cotton plants),
avoidance of susceptible alternate host crops (as okra,
sesame, egg plant, water melon, sun kukra, china rose,
thorn apple (dhatura), mint, karund, cucurbits, beans,
tomatoes, tobacco, chilies, soy bean, sun flower, cow
peas, holly hock, zinnia, sesame, citrus species etc.),
proper irrigation, soil and fertilizers management,
excellent weed control help in obviating the disease
effects.
4- Whitefly, Bemisia tabaci (Genn.) has been reported to
transmit CLCuV, therefore its early and effective
control should be ensured by applying the recommended
pesticides and with the cultural practices. Deep
plowing, clean cultivation, seed treatment with proper
fungicide, adequate manuring, proper plant spacing,
judicious irrigation, balanced and timely use of
fertilizer (especially nitrogenous fertilizers)
discourage the whitefly build up and reduce the risks of
infection.
5- Use of potassic fertilizers and foliar application of
micronutrients, especially zinc and boron at various
growth stages, as come under the practical experience of
the writer during several field trails, have proved
quite beneficial for eliminating or reducing the menace
of virus.
6- The application of hot air or heat treatments by
burning plant wastes in CLCuV-affected fields, and top
pruning of dissembled plants are found to be helpful in
quashing the virus deterioration.
As cotton is the mainstay of Pakistan's agrarian
economy, and a major share (about 60%) in foreign
exchange earnings, therefore all embracing efforts are
essential to cope with the present situation which is
fast deteriorating year after year. Top experts should
be engrossed in finalizing of steps necessary to be
taken by the farmers. Thereafter, it is a necessary part
of agriculture extension department to educate the
cotton growers and to aware those essential steps to be
taken before the cotton sowing season sets in. All the
necessary action should be taken steadfastly unless the
damages are to be stopped or reduced to the endurable
level.
It is out look and responsibility of the cotton growers
to adopt the modern agricultural techniques and play a
role for the development of the country.
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