identification, symptoms and nature of damage of plant- and leaf-hoppers
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Identification, symptoms and nature of damage of
Plant- and Leaf-hoppers
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Introduction
Rice is the world’s most important food crop and is the staple food for more
than half of the population. In India, rice is grown on about an area of 45.0
million hectares with a production of 89.0 million tonnes. However, rice
productivity of 3.01 t/ha in India is inferior to 6.26 t/ha in China and 3.51 t/ha in
Sri Lanka. There are over 800 insect species damaging rice in one way or other but
about 20 species are of major importance and of regular occurrence. The insect
pests cause huge economic loss to the rice-growing farmers in the developing
world.
Yield loss due to insect pests in rice has been estimated to the tune of 21 % to
50 %. The insect pest complex of the rice crop has undergone a drastic change
during the last three decades following the green revolution.
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Brown planthopper(BPH)
White-backed planthopper (WBPH)
Identification of Insect
Among 15 species of planthoppers and
leafhoppers known to infest rice in India, brown
planthopper (BPH), Nilaparvata lugens;
whitebacked planthopper (WBPH), Sogatella
furcifera, and green leafhopper (GLH),
Nephotettix virescens are most damaging ones.
The BPH caused wide spread devastation
of rice crop during kharif 2008 in north India
and again during kharif 2010, it was serious
in sporadic pockets. Yield loss could be as
high as 50-90%.
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Rice plants affected by tungro
Planthoppers on rice stems
Courtesy: agritech.tnau.ac.in
Nature of Damage
In general, planthoppers generally remain
confined to plant stems and leaf sheaths while
leafhoppers occur on plant foliage. Due to this
habit, planthoppers are overlooked by farmers until
appearance of ‘hopperburn’ symptoms in which
crop starts drying and lodging. However, during
outbreaks, planthoppers can be witnessed in
abundance on leaves also.
On other hand, leafhoppers feed on leaves and
damage the crop. However, they are more important
as vectors of virus disease “tungro”
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Green Leafhopper Courtesy: DPPQS
Planthoppers
Mark of identification
As the name indicates, BPH nymphs and adults are
brown in colour while WBPH nymphs are white or grey
and adults have a white stripe at their back.
The GLH adults are green with black spot and black
patch on wings. These can be seen moving sideways
on leaves.
The BPH and WBPH occur in long-winged
(macropterous) and short-winged (brachypterous)
forms. These are small insects measuring 3.0-4.5 mm.
The BPH is also known to undertake long range
migration.
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Crop damage (hopper burn) due to planthoppers
Both nymphs and adults of
planthoppers damage crop by
sucking sap from plant stems
and leaf sheaths, and as a result
leaves start turning yellow. If
not checked during initial
stages, population builds up
rapidly resulting in
“hopperburn”. In case of BPH
typical concentric circles of
hopperburn can be witnessed in
field. Besides direct damage,
BPH also transmits grassy stunt
virus disease in rice.End Previous Next
Planthopper damaged crop
Leaf hoppers also suck sap from leaves but these are more important as transmitters of tungro virus disease than as direct feeders.
Dense rice crop under continuously flooded conditions and excess use of nitrogenous fertilizers provides very congenial environment for planthopper population build up.
Irrigation should be applied in ‘alternate wetting & drying fashion’ and if planthopper population buildup is perceived then irrigation should be withheld for few days. Likewise, excess use of nitrogenous fertilizers be avoided with emphasis on balanced fertilizer use.
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Proper monitoring and
judicious use of fertilizers &
irrigation hold key to
planthopper management in
rice. Monitoring can be done by
inspecting plant stems at
several places in all parts of
field. As plant stems are tapped,
these insects fall on water and
can be seen swimming.
Likewise, light traps can also be
used for monitoring
planthoppers. Light trap
Planthoppers on plant stems
Management practices
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Spiders play very important role in
containing planthoppers and therefore
they should be conserved through
selective pesticide application. This can
be ensured through use of granular
formulation of pesticides or leaving
certain areas in the field untreated.
There is also practice of placing rice
straw bundles in field after
transplanting to encourage spider
population build up.
Economic threshold level (ETL): 8-10 hoppers/hill
Spiders
Management practices
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Let’s sum up
Yield loss due to insect pests in rice has been estimated to the tune of 25%.
Brown planthopper (BPH), whitebacked planthopper (WBPH) and green leafhopper (GLH), Nephotettix virescens are most damaging pests of rice
Both nymphs and adults of planthoppers damage crop by sucking sap from plant stems and leaf sheaths.
On other hand, leafhoppers feed on leaves and damage the crop. However, they are more important as vectors of virus disease “tungro”.
Dense rice crop under continuously flooded conditions and excess use of nitrogenous fertilizers provides very congenial environment for planthopper population build up.
Spiders play very important role in containing planthoppers and therefore they should be conserved through selective pesticide application.
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