Carnation latent virus

Carnation latent virus (CLV) is a plant pathogenic virus belonging to the genus Carlavirus within the Betaflexiviridae family. It primarily affects plants of the Dianthus genus, causing systemic infections that can lead to significant economic losses in the floriculture industry, particularly in carnation production.

The virus is characterized by its latent nature, meaning many infected plants remain asymptomatic or show only very mild symptoms such as slight leaf mottling, interveinal chlorosis, or subtle growth stunting. However, when combined with other viruses like Carnation mottle virus, it can cause severe plant decline, distorted flowers, and reduced bloom quality.

The biology of CLV involves mechanical transmission and vector-based spread. The virus is easily transmitted through contaminated sap during handling, pruning, or harvesting activities. Additionally, various aphid species act as non-persistent vectors, acquiring the virus during brief probes and spreading it rapidly throughout the crop. The virus replicates within the plant's cytoplasm and spreads systemically via the vascular system.

Development and spread of the virus are accelerated by high-density cropping systems and poor sanitation practices in greenhouses. Once introduced into a plant population, the virus is easily maintained through vegetative propagation, as infected cuttings serve as a continuous source of inoculum for subsequent generations of plants.

Managing Carnation latent virus is challenging because no curative chemical treatments exist. Therefore, control focuses on strict phytosanitary measures to prevent virus entry and spread. Recommended practices include:

• Sourcing virus-indexed, certified disease-free propagation material.
• Implementing rigorous sanitation protocols for tools and work surfaces, using appropriate disinfectants.
• Managing aphid populations through integrated pest management (IPM) to reduce transmission risks.
• Isolating new plant stocks before introducing them into the main greenhouse.
• Rogueing infected plants immediately upon detection to minimize field spread.