Carnation necrotic fleck and carnation streak

Carnation necrotic fleck and streak is a viral disease caused by the Carnation necrotic fleck virus (CNFV). This pathogen belongs to the Closterovirus genus and is known to cause severe systemic infections, significantly impacting the physiology and vitality of the host plant.

The disease primarily affects Dianthus caryophyllus (carnations). It is a significant concern for commercial cut-flower production, as infected plants become stunted and produce flowers of inferior quality, rendering them unsuitable for market distribution.

Key symptoms include the development of necrotic spots on the leaves, which often elongate into streaks. As the infection progresses, leaves may turn chlorotic and curl, and the overall plant vigor decreases drastically. Severe infections lead to stunted growth and reduced flower yields, often accompanied by leaf necrosis.

Transmission occurs primarily through aphid vectors, such as the green peach aphid (Myzus persicae). The virus is acquired by the aphid during feeding and transmitted to healthy plants. Another major pathway for the spread of the disease is the use of infected cuttings during the vegetative propagation of carnations.

Control strategies must focus on exclusion and sanitation to manage the infection. These include using virus-indexed propagation stock, strict control of aphid populations through integrated pest management programs, and the immediate rogueing of any plants displaying characteristic viral symptoms. Regular cleaning and disinfection of cutting tools and greenhouse surfaces are also essential to prevent mechanical transmission.