Sweet potato latent virus

Sweet Potato Latent Virus (SPLV) is a plant pathogen that specifically targets sweet potato (Ipomoea batatas) crops. Despite its name, the virus can have significant impacts on sweet potato yield and quality, particularly under conditions that favor its spread and development. This article provides an overview of Sweet Potato Latent Virus, including its characteristics, transmission, symptoms, management strategies, and economic importance.

Characteristics

Sweet Potato Latent Virus belongs to the genus Potyvirus, which comprises a large group of plant viruses. Like other members of this genus, SPLV is a single-stranded RNA virus. Its genome encodes for several proteins essential for the virus's replication, movement, and infection processes within the host plant. The virus is characterized by its filamentous particles, which are typical of potyviruses.

Transmission

SPLV is primarily transmitted through vegetative propagation of infected sweet potato cuttings. The virus can also be spread by aphids in a non-persistent manner. This means that aphids can acquire the virus after feeding on an infected plant for a short period and then transmit it to a healthy plant during subsequent feedings. However, the virus is not transmitted through seed or soil.

Symptoms

Infected sweet potato plants may exhibit a range of symptoms, which can vary depending on the virus strain, environmental conditions, and the sweet potato variety. Common symptoms include mild mottling and chlorosis of the leaves, which may not always be easily noticeable, hence the term "latent." In some cases, infected plants may show stunting or reduced growth, but these symptoms can be easily confused with nutrient deficiencies or other stress factors.

Management

Management of Sweet Potato Latent Virus focuses on preventive measures, as there are no chemical treatments available to cure infected plants. Key strategies include:

• Use of certified disease-free planting material: This is the most effective way to prevent the spread of SPLV. Growers should source sweet potato cuttings from reputable suppliers who test for the presence of SPLV and other pathogens.
• Control of aphid vectors: Since aphids can transmit the virus, controlling aphid populations through the use of insecticides or natural predators can help reduce the spread of SPLV.
• Crop rotation: Rotating sweet potatoes with non-host crops can help reduce the buildup of SPLV in the soil, although the virus is not soil-borne, this practice helps manage other soil-borne pathogens and pests.
• Rogueing: Removing and destroying infected plants from the field can help reduce the source of the virus for aphid transmission.

Economic Importance

While the symptoms of Sweet Potato Latent Virus may be mild or even unnoticeable, the virus can cause significant yield losses, especially in susceptible sweet potato varieties. The quality of sweet potatoes can also be affected, which may reduce their market value. As sweet potatoes are an important food crop in many parts of the world, managing SPLV is crucial for ensuring food security and the livelihoods of farmers.

Conclusion

Sweet Potato Latent Virus is a significant pathogen of sweet potatoes, capable of causing yield losses and affecting the quality of the crop. Effective management relies on preventive measures, including the use of disease-free planting material, control of aphid vectors, and good agricultural practices. Continued research and extension services are essential to develop and disseminate effective management strategies for SPLV.