Ecology, epidemiology

- Conservation, sources of viruses

The sources of contamination of the dandelion ( yellow mosaic virus Dandelion yellow mosaic virus , DaYMV) are not well known. To date, only lettuce and chicory, for cultivated plants, and dandelion ( Taraxacum officinale ), for weeds, can be considered as reservoir plants ensuring the conservation of this virus. On the other hand, DaYMV can be inoculated artificially into numerous plant species belonging to 5 botanical families. Not all of the isolates studied have the same host range. Spinach, peas and zinnia are found to be sensitive. Most wild lactuca, sow thistle (for some isolates) and several lamb's quarters are also infected in the laboratory.


- Transmission, dissemination

According to the literature, DaYMV is transmitted by some aphid species, but the information at our disposal is quite contradictory. The artificial transmissions produced have sometimes been found to be negative or have resulted in low rates of transmission to salads. Aphid species such as Myzus ornatus , Myzus ascalonicus and Acyrthosiphon solani could transmit it. The ability of Myzus persicae to transmit DaYMV would be low or zero according to the authors. Current experimental results suggest that its mode of transmission is semi-persistent, i.e. bites lasting ten minutes or more are required, both to acquire the virus from an infected plant and to to transmit it to a healthy plant. In addition, it is not impossible that, as in the case of another sequivirus, the presence of a second so-called "helper" virus is necessary for DaYMV to be able to be transmitted.

Current knowledge does not allow us to understand the wide dissemination of this virus. On the other hand, they conclude that it is not transmitted by seed in lettuce.