Dr. S.K. Dutta & Dr. Badal Bhattacharyya Department of Entomology Assam Agricultural University,Jorhat-13

1. 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

2. 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

3. 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

4. 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 Source:http://www.omafra.gov.on.ca/english/crops/f acts/06-081f9.jpg Fig. Potato leaf curl virus Source: http://www.fwi.co.uk/Articles/2010/ 01/16/111051/Potato-aphids.htm

5. 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

6. Nature of Damage: • The attacked plants give a sickly, black appearance with poor growth & yield Symptoms: Fig. Whitefly infested potato plant Source: http://www.google.com/imgres?imgurl=http://cipm.ncsu.edu/ent/southern_region • 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

7. 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 2c 3 Fig. Potato leaf hopper Source: http://m.cmeg.psu.edu/insects/potato-leafhopper.cfm

8. Nature of Damage: • Crinkling, curling and drying up of leaves (brick red or brown coloured) Symptoms: 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

9. 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: • Oily appearance of lower side of • leaves 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

10. 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 Lower surface Upper surface Fig. Potato mite Source: http:// www.sel.barc.usda.gov/acari/ content/broad/a.html Fig. Mite infested potato leaves Source: http://vegetablemdonline. ppath.cornell.edu/ Diagnostickeys/TomLeaf/Broad_Tom.htm