Ipomoea leaf curl Shandong virus

The primary symptom of infection is the severe curling of leaf margins, either upward or downward, often accompanied by the thickening and leathering of leaf tissues.

Infected plants frequently exhibit yellowing (chlorosis) along the veins or across the entire leaf blade, leading to a mosaic appearance that indicates impaired photosynthesis.

Growth is significantly stunted, with internodes becoming shortened and the plant taking on a bushy, rosette-like growth habit due to excessive lateral branching.

Symptoms become more pronounced on younger, developing leaves, which often show severe deformation and a reduction in overall surface area.

• Upward or downward leaf curling
• Yellowing (chlorosis) and mosaic patterns
• Stunted growth and reduced internode length
• Deformed, leather-like leaf texture

Ipomoea leaf curl Shandong virus (ILCSdV) is a DNA virus classified within the genus Begomovirus and the family Geminiviridae. It is a highly evolving pathogen capable of significant recombination with other whitefly-transmitted viruses.

The virus primarily affects plants in the Convolvulaceae family, with sweet potato (Ipomoea batatas) being the most economically significant host.

Transmission of the virus is carried out in a persistent manner by the whitefly Bemisia tabaci, which acts as the main vector for its spread within and between fields.

The viral genome consists of single-stranded DNA molecules packed within geminate-shaped capsids, which is a structural hallmark of the Geminiviridae family.

Due to its rapid replication cycle and high mutation rate, the virus poses a persistent threat to sweet potato production in warm and humid climatic regions.

The development and spread of the virus are heavily influenced by the population density of the whitefly vector, which thrives in warm and temperate climates.

High temperatures during the summer months accelerate both the reproduction of whiteflies and the viral replication within the host plant tissues.

Wild Convolvulaceae species in the vicinity serve as alternative hosts, acting as reservoirs for the virus during periods when the main crop is absent.

Propagation using infected cuttings is the primary method of long-distance dispersal, making the quality of planting material a critical factor in disease management.

Closed greenhouse environments with inadequate insect-proof screening facilitate rapid outbreaks of the disease due to the build-up of insect populations.

The economic impact of the virus is significant, as it leads to a drastic reduction in both the quantity and quality of marketable sweet potato storage roots.

Severe infection affects the plant's ability to store carbohydrates, resulting in smaller, malformed, or poor-quality roots that have little commercial value.

The virus can lead to the gradual degeneration of high-yielding varieties, forcing growers to replace their planting stock more frequently to maintain productivity.

Infection during the early vegetative stage can lead to substantial yield losses, as plants fail to develop a robust root system before the infection peaks.

The cumulative effect of reduced yield, increased costs for vector control, and the need for phytosanitary measures makes this virus a serious challenge for producers.

The use of certified, virus-free planting material derived from tissue culture is the cornerstone of effective management against this begomovirus.

Implementing an integrated pest management (IPM) strategy to control whitefly populations using systemic insecticides and biological controls is essential for disease suppression.

Strict sanitation practices, including the removal of infected plants and the destruction of weed hosts like wild bindweed, are vital to reducing viral inoculum.

Spatial isolation between new and older sweet potato plantings helps to prevent the migration of infected whiteflies from established fields to young crops.

Regular monitoring of field edges for signs of whitefly infestation and viral symptoms allows for early detection and rapid response to mitigate further spread.