Chinese yam mosaic virus

The Chinese yam mosaic virus (Macluravirus dioscoreachinense) is a plant virus within the genus Macluravirus and the family Potyviridae. As an RNA-based pathogen, it disrupts the vascular system and cellular metabolic processes of the host, leading to reduced vigor and systemic physiological imbalance.

The primary host for this virus is the Chinese yam (Dioscorea polystachya). This crop, valued for its starchy tubers, is susceptible to various viral pathogens, but the Macluravirus strain poses a significant challenge due to its ability to persist and spread efficiently through various modes of transmission.

Symptoms of an infection typically include foliar mosaic patterns, featuring yellow-green mottling or chlorotic spots. In advanced stages, leaves may become distorted or puckered, while the entire plant exhibits stunted growth. The impact on the tuber yield is substantial, often leading to smaller, misshapen tubers that fail to meet agricultural quality standards.

Transmission occurs primarily through aphid vectors in a non-persistent manner, meaning the insect can transmit the virus shortly after probing infected plant tissues. Additionally, the virus is often disseminated via contaminated propagation material, specifically infected tubers, which creates a cycle of reinfection in subsequent growing seasons.

Effective management strategy hinges on integrated pest management (IPM) practices. Key steps include the use of certified virus-free seed tubers, rigorous control of aphid populations using targeted insecticides, and the prompt rogueing of symptomatic plants. Maintaining field hygiene and controlling weed hosts are also essential to reduce the inoculum pressure in the environment.