Transcript PTM

Identification, symptoms and nature of damage: potato
tuber moth and cut worm
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Potato Tuber Moth
Identification:
The larvae are pinkish-white or greenish in colour with dark
brown head
They are about 20 mm in length
Larva
Adult
Fig. Adult of potato tuber moth
Fig. Larva of potato tuber moth
Source:http://www.fwi.co.uk/assets/getAsset.a
spx?ItemID=5225298
Source:http://4.bp.blogspot.com/0UlluG7ZKE0/TeeOgqQ
7NFI/AAAAAAAAAYs/j7XtDbecb0/s1600/1+Potato+tube
r+moth+phthorimaea_operculella_male.gif
The adult moth is very small (about 13 mm) and dark brown in
colour
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Symptoms:
In Field: Mined leaves and
drooping twigs of the plants are
the main symptoms of attack in
field
Fig. Field infestation of potato plants
by potato tuber moth
Source: http://www.infonet-biovision.org/default/images/139/crops
In Store: Tunnelling by larva leads to rotting and
foul smelling of tubers due to bacterial infection
Fig. Potato tubers damaged by the potato tuber moth.
Source: http://www.infonet-biovision.org/default/images/139/crops
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Nature of Damage:
Larvae mine the younger leaves and feed on the tubers
Larvae penetrate the leaves and feed within leaf veins or stems of the
plant
Larvae make irregular galleries and tunnel deep inside the tuber in
storage
The field infestation is caused either by the moths escaping from
godowns or by infested seed tubers
Larval Damage
Adult Damage
Fig. Potato field damaged by the larvae
Source: www.googleimages.co.in
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Fig. Potato tuber damaged by the larvae
Source: www.googleimages.co.in
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Cut worm:
Identification:
Larvae are dark grey or dull green with smooth and greasy
skin . The full-grown larva is 40-50mm in length
The adult is a heavy bodied, greyish-brown or wheat coloured moth
and measures 5.0-6.2 cm in length. The adults are strong fliers,
found on the hills (in summer) and plains (in winter)
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Fig. Different life stages of cutworm 1: Egg 2: Larva 3: Pupa 4: Adults
Source: AINP on White grubs, Department of Entomology,
Assam Agricultural University, Jorhat-13
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Symptoms:
Cutting down the young potato plants just above or slightly below the
surface of the soil
Fig. Cut worm infested potato seedlings
Source: AINP on White grubs, Department of Entomology,
Assam Agricultural University, Jorhat-13
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Nature of Damage:
Larvae spend the day hiding near the bases of potato plants (5-10
cm of top soil) and at night they come out and cut the young plants
just above or slightly below the surface of the soil
Larvae are voracious feeders and they cut or fell more plants than
they can consume
After tuber formation, they nibble and bore into the tubers affecting
both tuber yield and market value
Fig. Cut worm infested potato seedlings and tubers
Source: AINP on White grubs, Department of Entomology,
Assam Agricultural University, Jorhat-13
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