Sweet potato leaf curl Guangxi virus

The primary symptom is the characteristic curling of leaves, often accompanied by tissue deformation and discoloration. Leaf margins may curve upward or downward depending on the variety.

Significant leaf distortion occurs, resulting in a wrinkled and uneven leaf surface. Symptoms often manifest as mosaic patterns or chlorotic spots, severely affecting the plant's photosynthetic ability.

Infected plants exhibit stunted growth with shortened internodes, leading to a dwarf or bushy appearance that is particularly noticeable in early growth stages.

In severe cases, the plant shows general decline, with yellowing of older leaves and premature leaf drop, which adversely impacts storage root formation.

• Curling and distortion of leaves.
• Mosaic patterns and chlorosis.
• Stunted growth and reduced internodes.
• Overall loss of plant vigor.

The causative agent of the disease is Begomovirus ipomoeaguangxiense, a member of the Geminiviridae family. This is a single-stranded DNA virus prevalent in tropical and subtropical regions.

The genus Begomovirus is characterized by its transmission via insect vectors, primarily whiteflies of the Bemisia genus. The virus infects the vascular system, spreading systemically throughout the plant.

The virus's biological activity is closely linked to the lifecycle of its insect vectors, which acquire the virus while feeding on infected plant sap and transmit it to healthy hosts.

This virus is a specialized pathogen frequently identified within viral complexes affecting crops in the Convolvulaceae family.

Genetic analysis reveals high homology with other begomoviruses, which necessitates advanced molecular diagnostic techniques such as PCR for reliable identification.

Disease development is directly dependent on the population density of the whitefly vector. Hot and dry weather conditions favor rapid insect reproduction and facilitate virus transmission.

The virus spreads efficiently in climates where perennial host plants are present year-round. Many weed species from the Convolvulaceae family serve as constant virus reservoirs.

The use of infected planting material, such as vegetative cuttings, is a critical pathway for the long-distance spread of the virus and the creation of new infection hotspots.

Agronomic practices such as high-density planting and failure to implement crop rotation create a microclimate ideal for vector proliferation and virus accumulation.

Optimal temperatures for viral replication fall within the 25–30 degrees Celsius range, which also accelerates the metabolism of the insect vectors.

The economic impact of the virus is significant due to reduced yield potential, as distorted foliage severely limits the plant's ability to produce storage roots.

Tuber quality is drastically reduced, with storage roots becoming smaller, deformed, and unmarketable, leading to substantial financial losses for growers.

Infected plants have compromised immune systems, making them highly susceptible to secondary bacterial and fungal infections, which further reduces harvest quality.

The ability of the virus to spread via infected cuttings poses a major risk to clean seed stock programs and can lead to total crop failure if quarantine measures are ignored.

Persistent presence of the pathogen in a field leads to soil contamination and necessitates long periods without planting the susceptible crop to break the disease cycle.

The most effective prevention strategy is the use of healthy, certified planting material derived from tissue culture (meristem-tip culture) to ensure freedom from the virus.

Rigorous monitoring and management of whitefly populations using appropriate insecticides and exclusion techniques, like insect-proof nets, are essential.

Proactive weed management around planting sites helps reduce natural virus reservoirs, as many local weeds serve as latent hosts for the virus.

Implementing effective crop rotation and maintaining spatial isolation between new sweet potato plantings and existing fields helps break the transmission cycle.

Prompt rogueing and destruction of any plants showing early symptoms are mandatory to minimize the spread of the virus to healthy parts of the field.