Sweet Potato Vine Borer

📖 Description

Omphisa anastomosalis — the Sweet Potato Vine Borer — is a pyralid moth pest of sweet potato in India, with economic significance centred on the sweet potato belts of Odisha (Cuttack, Puri, Balasore, Mayurbhanj — India’s largest sweet potato-growing state), Uttar Pradesh (Bareilly, Budaun, Shahjahanpur), Bihar (Muzaffarpur, East Champaran, Samastipur), West Bengal (Midnapore, Bankura, Purulia), Assam (Darrang, Nagaon, Morigaon), and Tamil Nadu (Cuddalore, Villupuram, Vellore). India is the world’s second-largest sweet potato producer (~1.4 million tonnes from ~0.12 million ha), with sweet potato serving as a critical food security crop in tribal and rainfed areas of Odisha, Bihar, and Jharkhand — it produces more food energy per hectare per day than any other major crop. The pest is native to tropical Asia but has spread throughout the tropics — it was first reported as a major pest of Indian sweet potato in the 1980s and has since become established as the most damaging stem borer of sweet potato in eastern and northeastern India. The pest’s biology makes it particularly damaging: (1) eggs are laid in small clusters on the underside of leaves or on the soil surface near the plant base — inconspicuous and difficult to detect; (2) larvae are concealed inside the main vine, crown, and storage roots — protected from contact insecticides; (3) pupation occurs inside the vine or in soil — protected from foliar insecticides; (4) wide host range (all Ipomoea species) — survives on wild Ipomoea weeds on field margins between sweet potato crops; and (5) internal root damage is often misdiagnosed as ‘rot’ or ‘wet rot’ — by the time damage is detected, the larva has already destroyed the storage root. The economic impact is severe: heavy infestations can destroy 30–50% of plants in a field, reducing storage root yield by 40–70%. With sweet potato valued at ₹10–20 per kg in tribal markets (where it is a staple food), even moderate infestations cause significant food security and economic loss — for a typical Odisha tribal farmer cultivating 0.5 ha of sweet potato (yield 12–15 t/ha), a severe O. anastomosalis infestation can wipe out ₹30,000–60,000 of annual household food and income. Management is best achieved through IPM combining tolerant varieties (Sree Bhadra, Sree Kanaka — CTCRI-released varieties), certified pest-free vine cuttings, 2-year crop rotation, Ipomoea weed management on field margins, light trap monitoring, NSKE 5% foliar sprays during peak oviposition, mechanical removal of wilted vines, and deep summer ploughing. The Central Tuber Crops Research Institute (ICAR-CTCRI, Thiruvananthapuram) is the primary research institution for sweet potato IPM in India and maintains a network of field stations in Bhubaneswar (Odisha) and Ranchi (Jharkhand) for testing tolerant varieties in eastern India.