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Cotton crop under threat of 'army worm' attack
Lahore-Some 80,000 acres of cotton crop had to be destroyed in
Dera Ghazi Khan during the current season on the reports of
helio commonly known as "American Sundhi" outbreak in many
fields in the cotton belt of Punjab and some areas in Sindh.
Many cultivators in Sahiwal had to remove their crop after an
early first picking because the crop had been badly damaged by
the pest. Besides, the crop was also damaged in the Nara belt,
Sanghar following appearing of a disease locally known as "Garho
Pani."
The persistent drought-like situation has resulted in reduced
water discharge in the canals and the lowering of underground
water-table. This phenomenon proved a blessing as it rendered
thousand of acres of semi waterlogged area - which had become
illegal paddy growing area in the cotton belt- for for cotton
crop particularly in Ghotki, Sukkur, Khairpur and Naushero
Feroze. But due to water shortage many canals at Sukkur and
Guddu Barrage had to be closed for about a month, besides
placing some on rotation.
This resulted late sowing of rice and cotton crop in the upper
Sindh region during the current Kharif season. Due to the
erratic and late supply of water in canals, variations in the
stages of cotton crop is rampant. The extent of variation
could be gauged from
the fact that the early sown crop is under cotton picking,
whereas the late sown crop is still under inter-culturing and
early boll formation stage requiring two more months to get
forfeitable yield, if weather and pests permits.
The pest situation in upper Sindh cotton belt remained
normal.All over world, where cotton is produced there are
major pest problems and to control it, judicious use of the
pesticides is a prerequisite as its irrational use can yield
worst results. In Ghotki this year, as per field survey, an
estimated 3000 acres of standing cotton crop has come under
low to severe "army worm" attack. The cotton field, adjoining
forest, orchards, banana and tall trees are the worst victim
of this menace.
The survey has indicated that larvae of army worm have eaten
off the entire leaves denuding the very cotton plant, besides
damaging the young bolls, squares and flowers. A cotton grower
at Deh Wadpagya applied 11 different pesticides to control
this menace, but in vain.
However, repeated use of methamedophos, either alone or in
combination with the other group of pesticides were found
rampant in Ghotki. So far, only 15 to 20 per cent damage is
expected to the sanding early sown crop because majority of
bolls have attained maturity. However, late sown crop may
sustain severe damage because
the majority of bolls are still in the stage of lint
development.
The irrational use of pesticides has often created problems
more serious than those for which they were originally
applied. These include target pest resurgence, secondary pest
outbreak, development of insecticide-resistant pest strains,
toxic residues on adjacent crops, adverse impact on non-target
organisms, and pesticide biomagnification on ecological food
chains. Since army worm is not a regular and major pest of
cotton in Sindh, its outbreak may be attributed to aggressive
and injudicious use of pesticides in Ghotki.
The army worm: Its female lay eggs in cluster on the lower
leaf surface, the young worms are green which on becoming full
grown are nearly 1.5 inches long. Due to their feeding at
night, there presence is generally not suspected until the
crop is nearly
destroyed. This insect fluctuates greatly in abundance. During
epidemics it often destroys much of the vegetation over
hundreds of square miles.
November 23, 2001
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