Symptoms and Control Methods of Carnation Vein Mottle Virus Disease
[Symptoms] Systemic mosaic, vein mottling, symptoms masked in old leaves in winter. Flower color breaking, especially severe petal color breaking in red varieties.
[Pathogen] Carnation vein mottle potyvirus (CaVMV). Particles are filamentous, 790nm×18-19nm, also reported as 600-710nm×13nm. Sedimentation coefficient approximately 144S. A260/280=1.15. Antiserum tests show it is related to the Potato virus Y genus. Thermal inactivation point (TIP) 60-65°C; dilution end point (DEP) 10-3 to 10-5; longevity in vitro (LIV) 2-10d at 13°C. Virus particles are dispersed in the cytoplasm and have pinwheel-shaped inclusion bodies. Carnation vein mottle virus and Carnation latent virus can be distinguished by serological reaction and electron microscopy observation. Inoculation testing with Dianthus barbatus (Sweet William) is most convenient, because Carnation latent virus cannot cause symptoms in Dianthus barbatus. Other carnation viruses (such as mottle, ringspot, etched ring, Italian ringspot) all have isometric symmetrical particles, and all cause corresponding indicator plants to show obvious symptoms.
There are few studies on strains of this virus. It has been found that although different isolates cause similar symptoms in carnations, they differ in their ability to infect Chenopodium amaranticolor; the typical strain infects Gomphrena globosa and Amaranthus caudatus causing systemic vein mottling, while other isolates do not infect them. Their longevity in vitro also shows minor differences.
[Disease Development] Myzus persicae transmits the virus in a non-persistent manner. It can be transmitted by sap. It has not yet been found that seeds of Chenopodium amaranticolor and Dianthus barbatus can transmit the virus. If virus-carrying plants are used as cutting material, the virus will cause a major outbreak.
[Control]
1. Carnation plants are difficult to free from the virus by heat treatment, but are easily freed from the virus by shoot tip culture. Use virus-free seedlings as propagation mother plants and establish a virus-free mother plant base.
2. Use 40% dimethoate emulsifiable concentrate at 1000 times dilution, or 40% omethoate emulsifiable concentrate at 1000 times dilution, or 80% dichlorvos emulsifiable concentrate at 1000 times dilution, etc. to control aphids and reduce vector insects.
3. Pay attention to field sanitation management, emphasize tool disinfection, and reduce human-mediated transmission.
4. Emphasize disease-resistant breeding. Dianthus chinensis (China pink) has strong disease resistance, but its flowers are small and flower color is poor; while carnations have the characteristics of large flowers and bright colors. Use various measures to breed new carnation varieties with multiple excellent traits and strong disease resistance.