Dr. S.K. Dutta & Dr. Badal Bhattacharyya Department of Entomology

1. Identification, symptoms and nature of damage: potato tuber moth and cut worm Dr. S.K. Dutta & Dr. Badal Bhattacharyya Department of Entomology Assam Agricultural University,Jorhat-13

2. 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. Larva of potato tuber moth Source:http://www.fwi.co.uk/assets/getAsset.a spx?ItemID=5225298 Fig. Adult of potato tuber moth Source:http://4.bp.blogspot.com/0UlluG7ZKE0/TeeOgqQ7NFI/AAAAAAAAAYs/j7XtDbecb0/s1600/1+Potato+tuber+moth+phthorimaea_operculella_male.gif • The adult moth is very small (about 13 mm) and dark brown in colour

3. 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

4. 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 Fig. Potato tuber damaged by the larvae Source: www.googleimages.co.in

5. 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) 1 2 3 4 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

6. Cutting down the young potato plants just above or slightly below the surface of the soil Symptoms: Fig. Cut worm infested potato seedlings Source: AINP on White grubs, Department of Entomology, Assam Agricultural University, Jorhat-13

7. 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