Transcript Slide 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 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 Fig. Larva of potato tuber moth Source:http://www.fwi.co.uk/assets/getAsset.a spx?ItemID=5225298 Adult Fig. Adult of potato tuber moth 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 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 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 Fig. Potato field damaged by the larvae Source: www.googleimages.co.in Adult Damage Fig. Potato tuber damaged by the larvae Source: www.googleimages.co.in 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 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 Nature of Damage: Larvae spend the day hiding near the bases of potato plants (510 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