Transcript Aphids leaf hoppers white fly mites 97

Identification, symptoms and nature of damage:
aphids, white fly, leaf hoppers and mites
Dr. S.K. Dutta & Dr. Badal Bhattacharyya
Department of Entomology
Assam Agricultural University,Jorhat-13
Aphids:
Identification:
Aphids are minute (2-2.5 mm long), delicate, pear-shaped,
yellowish-green winged or wingless insects
Fig. Potato aphid
Source: http://ipmworld.umn.edu/aphidalert/alert5.html
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
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. Sooty Mould
Fig. Potato leaf curl virus
Source:http://www.omafra.gov.on.ca/english/crops/f
acts/06-081f9.jpg
Source: http://www.fwi.co.uk/Articles/2010/
01/16/111051/Potato-aphids.htm
White fly:
Identification:
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
Fig. White Fly
Source: http://www.spraytec.com/images/whitefly.jpg
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
Leaf hopper:
Identification:
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
1
2
Fig. Potato leaf chopper
3
Source: http://m.cmeg.psu.edu/insects/potato-leafhopper.cfm
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 hopper
Source: http://web3.canr.msu.edu/vanburen/plh.htm
Mite:
Identification:
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
Symptom:
Male
2
c
3
Oily appearance of lower side of
leaves
Female
Fig. Male and female potato mites
Source: Dr. D.C. Borah, Ex. Prof. & Head, Department of Entomology, Assam Agricultural University,
Jorhat-785013
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
Fig. Potato mite
Source: http:// www.sel.barc.usda.gov/acari/
content/broad/a.html
Lower surface
Fig. Mite infested potato leaves
Source: http://vegetablemdonline. ppath.cornell.edu/
Diagnostickeys/TomLeaf/Broad_Tom.htm