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A.
Incidence of Woolly aphid in India and other countries:
The
incidence of aphids as sucking pest is common on
sugarcane crop in India. The occurrence of sugarcane
woolly aphid, Ceratovacuna lanigera (Zehntner) has been
recently noticed to cause damage in sugarcane crop. The
woolly aphid was recorded earlier on sugarcane from
North-Eastern States like Nagaland, Assam, Tripura,
Sikkim and also from West Bengal and even from Uttar
Pradesh but there was no infestation on sugarcane crop.
Earlier, this pest was merely listed as minor pest of
sugarcane. Sugarcane woolly aphid is also known as main
pest of sugarcane in tropical Asian region i.e.
Phillippines, Indonesia, Taiwan, Chaina, Japan, Korea
besides a record from Pakistan. Sugarcane is a primary
host of this aphid while bamboo, Miscanthus sinensis and
Cynodon dactylon are the secondary hosts.
B.
Nature of injury, losses, life cycle of woolly
aphid The nymphs and adults of sugarcane woolly aphid
congregate on the central surface of leaves along midrib
and desap resulting in drying up of leaves besides
excreting honey dew on the upper surface of the lower
leaves on which fungus develops quickly resulting in
'sooty mould' showing complete blackening of leaves,
Sooty mould affect photosynthesis, resulting quality and
quantity. Favourable climatic conditions enhance the
reproduction capacity and in a short period a huge
population is reproduced. During severe infestation on an
average 1600 nymphs may be found on a single leaf to a
maximum of 8000 nymphs. The winged female of wooly aphid
can fly with wind to a distance of 1.5 km to 2.0 km. This
facilitates further spread of the pest. The life cycle of
this aphid is completed in a period of one month
depending on the climatic conditions and sugarcane
varieties.
C.
MANAGEMENT OF THE WOOLLY APHID IN SUGARCANE
- In endemic
pockets, promote paired or wider row planting to
help take up pest management practices. The
spacing recommended in this regard for the
different states is detailed below.
| State |
Spacing (cm) |
| Maharashtra
& Karnataka |
75 x 150 |
| Andhra
Pradesh |
30 x120 |
| Tamil
Nadu |
45 x 120 |
| Uttar
Pradesh |
30 x 60 |
- Adopt proper
water management practices and avoid excess
irrigation. If possible adopt drip irrigation.
- Select seed
material with care from pest free areas and
uninfested fields.
- Destroy
affected leaves when the pest problem is
initially noticed in a limited area, which helps
prevent the spread of the pest.
- Utilise
sugarcane varieties less susceptible to the
woolly aphid.
- Adopt crop
habitat diversity through intercropping in
sugarcane ecosystem to reduce the pest
population.
- In summer
treat the epicenters of woolly aphid infestation
with dichlorvos to prevent further population
build up. If natural enemies like Dipha, Micromus
etc are seen, chemicals should not be sprayed.
- Integrated
nutrient management incorporating organic manures
like FYM / vermicompost, etc., @ 20 t/ha and
avoiding excess application of nitrogen. The
fertilizer recommendations vary from state to
state.
- Regular
surveillance and monitoring of sugarcane woolly
aphid for timely forewarning and adoption of BIPM
measures.
- Biological
Control
- Conserve
and augment natural enemies like Dipha
aphidivora, Micromus igorotus, syrphids, etc.
by avoiding the use of chemical pesticides
whenever natural enemy activity is seen.
- Ensure
that no chemical pesticides are used in at
least 1 % of the sugarcane field to serve as
a refuge for the build - up of natural
enemies.
- Set up
Dipha aphidivora and Micromus igorotus
nurseries under shade nets and augment their
population in woolly aphid - infested areas
by periodic releases especially during June -
July. Augmentation may also be effected
during this period from fields where Dipha is
present to fields where it is absent.
- In
instances where the pest has reached
uncontrollable proportions and use of
chemical pesticides is inevitable, pesticides
may be used as per approved policy of the
state government.
- Many
pesticides have been found to be effective
against the SWA. They may be used only as a
last resort and with caution. However since
methyl-parathion and phorate are highly toxic
they should be avoided wherever possible.
Since malathion has low mammalian toxicity it
may be preferred over the other pesticides.
- The
pesticides endosulfan , malathion ,
chlorpyriphos, acephate, methyl demeton,
dichlorvos, phorate or carbofuron, dimethoate
and metasystox have been recommended for the
management of the sugarcane woolly aphid by
different agencies (Central Team headed by
the Agricultural Commissioner, GOI; VSI,
Pune; UAS, Dharwad; TNAU, Coimbatore; SBI,
Coimbatore and ZARS, Mandya - UAS, Bangalore
).
- Soil
application of granular insecticides will be
less harmful to the predators but sufficient
waiting period of at least 60 days should be
allowed before harvest.
CAUTION
- While
adopting chemical control measures Good
Agricultural Practices should be adopted and
indiscriminate/ excess use of pesticides
should be avoided at all cost.
- Ensure
that insecticide treated leaves are not used
as fodder.
- Resorting
to chemical control may upset the biological
balance by destroying the predators and
parasitoids and result in flare up sucking
pests like Pyrilla, scales and mealybugs.
- Prompt
harvesting of cane should be ensured to reduce
the development of woolly aphid population.
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