Identification, symptoms and nature of damage: aphids, white fly, leaf hoppers and mites

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Aphids:

Aphids are minute (2-2.5 mm long), delicate, pear-shaped, yellowish-green winged or wingless insects

Identification:

Fig. Potato aphidSource: http://ipmworld.umn.edu/aphidalert/alert5.html

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Symptoms:

Weak and stunted growth of the plants

Black sooty mould growth on leaves

Fig. Aphid infested potato plant

Source: http://www.google.com/imgres?imgurl=http://cipm.ncsu.edu/ent/southern_region

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Nature of Damage:

Both nymphs and adults of aphids suck the plant sap from leaves, terminal buds, inflorescence etc. and plants become weak

The honey dew secreted by aphids favours growth of sooty mould which inhibits photosynthesis and thus reduces yield

This insect also transmits viral diseases

Fig. Potato leaf curl virusSource: http://www.fwi.co.uk/Articles/2010/

01/16/111051/Potato-aphids.htm

Fig. Sooty Mould Source:http://www.omafra.gov.on.ca/english/crops/f acts/06-081f9.jpg

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White fly:

The adult is a small delicate insect with yellow body and transparent waxy wings. They are 1.0 -1.5 mm long

The nymphs are slow-moving, louse like and elliptical in shape

Identification:

Fig. White FlySource: http://www.spraytec.com/images/whitefly.jpg

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Symptoms:

The attacked plants give a sickly, black appearance with poor growth & yield

Fig. Whitefly infested potato plant

Source: http://www.google.com/imgres?imgurl=http://cipm.ncsu.edu/ent/southern_region

Nature of Damage:Both nymphs and adults suck cell sap from the potato leaves and reduce the vitality of the plants

The honey dew secreted by the whiteflies favours growth of sooty mould which hampers photosynthesis by the plants

This insect also transmits viral diseases

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Leaf hopper:

Adults are greenish yellow during the summer and become reddish in winter

They are about 3mm long

The winged adults jump or fly away at the slightest disturbance and are also attracted to light at night

Identification:

1 2c

3 Fig. Potato leaf hopper

Source: http://m.cmeg.psu.edu/insects/potato-leafhopper.cfmPreviousEnd Next

Symptoms: Crinkling, curling and drying up of leaves (brick red or brown coloured)

Nature of Damage:

Injury to the leaves is caused by nymphs and adults due to their sucking habit and injection of toxic saliva

The attacked leaves turn pale and then rust red. With change in appearance, the leaves also curl downwards, dry up and fall to the ground

Fig. Potato plants infested by leaf hopperSource: http://web3.canr.msu.edu/vanburen/plh.htm

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Mite:

Male mites are small and white to pale yellow in colour. Females are yellowish and bigger than the males

They are active and fast moving

Identification:

2c

3

Male Female Fig. Male and female potato mites

Source: Dr. D.C. Borah, Ex. Prof. & Head, Department of Entomology, Assam Agricultural University, Jorhat-785013

Symptom:

Oily appearance of lower side of leaves

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Nature of Damage:Adults and nymphs damage the crop by foliage feeding

Mite attack starts from the top leaves showing downward curling in the early stages of infestation, the lower side of leaves appears 'oily'. Gradually these symptoms can be seen on the entire plant.

The infested leaves become short and leathery in appearance with characteristic copper colour deposits on lower side

Under severe mite attack, the infested leaves dry up and wither away resulting in death of the plant

Upper surface Lower surface

Fig. Mite infested potato leaves Source: http://vegetablemdonline.ppath.cornell.edu/ Diagnostickeys/TomLeaf/Broad_Tom.htm

Fig. Potato miteSource: http:// www.sel.barc.usda.gov/acari/ content/broad/a.html

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