Sweet potato leaf curl virus

Pathogen and disease type: Sweet potato leaf curl virus (SPLCV) is a member of the genus Begomovirus within the Geminiviridae family. It is a viral disease that systemically affects plant tissues. The pathogen is characterized by its geminate (twinned) particle morphology and a circular single-stranded DNA genome, which allows it to thrive within the host's vascular tissues.

Host range: The primary host for this virus is the sweet potato (Ipomoea batatas). However, the pathogen also infects various wild species within the Convolvulaceae family. These wild relatives act as significant reservoirs, enabling the virus to persist in agricultural landscapes even during seasons when sweet potatoes are not actively growing.

Symptoms and signs: The most diagnostic symptom is the upward curling of leaf margins, which gives the foliage a stunted and distorted appearance. Infected plants often exhibit mosaic patterns, yellowing (chlorosis), and an overall reduction in leaf size. In advanced stages, the systemic infection results in significant stunting and poor root tuber development, leading to substantial yield losses.

Conditions for development and spread: The virus is transmitted in a persistent, circulative manner by the sweet potato whitefly (Bemisia tabaci). Once a whitefly ingests the virus, it remains infectious for the remainder of its life. The spread of the disease is highly dependent on whitefly population dynamics, which are favored by warm, dry weather conditions and the presence of abundant host plant vegetation.

Management and prevention measures:

• Use of certified virus-free vegetative cuttings for planting.
• Systematic removal and destruction of wild Convolvulaceae weeds.
• Management of whitefly populations using targeted chemical and biological control agents.
• Implementation of physical barriers or insect-proof netting in greenhouse environments.
• Selection of sweet potato cultivars that demonstrate natural tolerance or resistance to the virus.