Occurrence and Control Methods of Carnation Viral Diseases in Protected Cultivation
Symptom Identification
Carnation Vein Mottle Virus Disease
When carnation is infected by Carnation vein mottle virus, it infects carnation, China pink (Dianthus chinensis) and American pink (Dianthus barbatus), all producing systemic mosaic, and in winter the old leaves often show symptom masking. Discolored spots appear on the petals, and the symptoms are especially obvious on red large-flowered cultivars.
Carnation Latent Virus Disease
After carnation is infected by this virus, it generally shows no symptoms, or has mild mosaic symptoms. But when Carnation latent virus and Carnation vein mottle virus infect together, mosaic symptoms are produced.
Carnation Necrotic Fleck Disease
After carnation is infected by Carnation necrotic fleck virus, on the leaves in the middle part of the carnation plant there are grayish-white, pale yellow necrotic mottling, or irregular streaks and stripes. The symptoms on the lower leaves of the plant are the same as those in the middle, but the necrotic spots are purplish-red. When the disease is severe, the entire leaf withers and necroses.
Carnation Etched Ring Disease
Carnation etched ring disease mainly attacks the leaves of carnation. On the leaves of large-flowered carnation cultivars, ring-patterned, ring-shaped or broad-striped necrotic spots are produced. When Carnation etched ring virus and Carnation vein mottle virus infect together, these symptoms are even more obvious. The symptoms are obvious at the seedling stage of carnation, and there is symptom masking in the hot season. When the disease is severe, many grayish-white ring-patterned spots merge with each other to become large disease spots, and the leaves curl and become deformed.
Disease Development Pattern
Carnation Vein Mottle Virus Disease
Carnation vein mottle virus is the pathogen of this viral disease. It is transmitted by sap, and can also be transmitted non-persistently by the green peach aphid (Myzus persicae); during horticultural operations (such as cutting flowers, removing buds, pruning, etc.) tools and hands can also transmit the virus. Virus-carrying seedlings can spread the disease over long distances. The severity of vein mottle disease is closely related to the peak period of the aphid population. After the peak period of the aphid population, vein mottle disease occurs severely.
Carnation Latent Virus Disease
Carnation latent virus is the pathogen of this viral disease. It is transmitted by sap, and can also be transmitted non-persistently by the green peach aphid (Myzus persicae). This virus infects plants such as carnation, American pink (Dianthus barbatus), pink (Dianthus), and Dianthus japonicus.
Carnation Necrotic Fleck Disease
Carnation necrotic fleck virus is the pathogen of necrotic fleck disease. It is transmitted non-persistently by the green peach aphid (Myzus persicae), and can also be transmitted by sap, but the success rate of sap inoculation is very low. Carnation necrotic fleck virus can also infect plants such as American pink (Dianthus barbatus).
Carnation Etched Ring Disease
Carnation etched ring virus is transmitted by sap and grafting, and can also be transmitted non-persistently by the green peach aphid (Myzus persicae). During horticultural operations, tools and hands can also transmit it. When carnations are planted too densely, the leaves of diseased and healthy plants rub against each other, which can aggravate the occurrence of the disease. Besides infecting carnation, etched ring virus also infects plants such as American pink (Dianthus barbatus) and Dianthus caryophyllus. Plants of the genus Saponaria are extremely sensitive to infection by etched ring virus.
Control Measures Strengthen quarantine to control the occurrence of the disease.
Strict quarantine must be carried out on carnation tissue-culture seedlings introduced from abroad; virus-carrying seedlings that are detected must be thoroughly destroyed, or treated before planting. Establish a virus-free mother plant garden for collecting cuttings for propagation
Take 0.2-0.7 mm stem tips from healthy plants as material for virus-free tissue culture; the survival rate of tissue-culture seedlings is high, and the virus-free rate is also high. Improve maintenance and management to control the spread of the disease. The mother stock source garden and the cut flower production garden should be set up separately to ensure that the stock source garden is not re-infected. Pruning, cutting flowers and other operation tools and hands must be repeatedly washed and disinfected with 3%-5% trisodium phosphate solution, alcohol or hot soapy water, to ensure a good sanitary environment for large-scale commercial production of carnation cut flower gardens.
Chemical Control
Control aphids to prevent the disease; spray 20% Virus A wettable powder at 500 times dilution, or 1.5% Zhibingling aqueous solution at 800-1000 times dilution, or 83 resistance inducer at 100 times dilution. Spray once every 10 days, for 2-3 consecutive sprays.