Ipomoea golden mosaic virus

The primary symptom is a distinctive bright yellow or golden mosaic pattern on the leaves, often appearing as interveinal chlorosis that forms a network-like appearance.

Infected plants frequently exhibit foliage deformation, including curling, crinkling, and stunted growth. The overall plant development is significantly retarded, resulting in a bushy or stunted architecture.

As the infection progresses, leaves may develop necrotic lesions, leading to leaf drop and systemic weakening of the plant's vascular system.

• Bright yellow/golden mottling on leaf surfaces.
• Leaf distortion and curling.
• Reduced plant size and stunted growth.
• Diminished flowering and reproductive capacity.
• Necrotic spots on mature leaves.

Symptom severity varies based on the host cultivar, the stage of development at the time of infection, and environmental stressors such as heat and drought.

The causative agent is the Ipomoea golden mosaic virus (IPGMV), belonging to the Begomovirus genus within the Geminiviridae family. It is a single-stranded DNA virus that predominantly infects plants of the Convolvulaceae family.

The disease is classified as a systemic viral mosaic. The virus infects the plant's phloem, where it hijacks cellular machinery to replicate, causing metabolic dysfunction and physiological decline in the host plant.

The biological stability of the virus in the environment is low; it relies entirely on living host plants and insect vectors to persist and spread within agricultural landscapes.

Genetic variability of the virus poses a significant challenge for plant breeding, making it difficult to develop resistant crop varieties that can maintain productivity under high viral pressure.

Transmission occurs exclusively through insect vectors, specifically whiteflies (Bemisia tabaci), which acquire the virus while feeding on infected plant tissues and inject it into healthy plants.

The development and spread of the disease are directly driven by the population dynamics of the whitefly vector, which thrives in warm and dry climate conditions.

Alternative hosts, particularly weeds in the Convolvulaceae family, serve as essential reservoirs for the virus during off-seasons, ensuring its survival near cultivated fields.

Agricultural practices that promote the overlapping of cropping seasons provide continuous availability of host plants, facilitating the rapid build-up and migration of viruliferous whitefly populations.

High temperatures accelerate both the lifecycle of the insect vector and the replication rate of the virus within the host tissues, intensifying the damage during the growing season.

Poor sanitation, such as leaving infected plant debris in the soil, facilitates the persistence of the virus and the presence of vectors in subsequent growing cycles.

The virus poses a severe threat to sweet potato production, resulting in substantial yield losses and poor quality of tubers, making them unmarketable for commercial use.

Infected plants exhibit reduced photosynthesis and starch accumulation, leading to small, misshapen, and underdeveloped tubers that lack nutritional and market value.

Economic losses are compounded by the high cost of monitoring and the necessity of intensive insecticide applications required to control the vector populations.

Systemic viral infection suppresses the plant's natural immune response, making crops more susceptible to secondary pathogens and further reducing overall field performance.

In extreme cases, localized epiphytotics can lead to total crop failure, forcing growers to abandon cultivation of susceptible varieties in endemic regions.

The most effective strategy for disease management is the systematic control of whitefly populations through the timely application of insecticides to reduce transmission events.

The use of virus-free, certified planting material is the foundational requirement for preventing initial outbreaks and ensuring healthy crop establishment from the start.

Sanitation practices, including the aggressive removal of weed reservoirs and the immediate roguing and destruction of symptomatic plants, are critical to lowering the inoculum pressure.

Implementing a strict crop rotation cycle using non-host plants helps to break the disease cycle and disrupts the habitat requirements of the whitefly vectors.

Integrated Pest Management (IPM) programs, which combine chemical control with cultural practices and monitoring, offer the best chance for long-term sustainable production in affected areas.