Guillaume wrote:It s not a virus infected vft because leaf cutting did not produce variegated vft, the only wait to have spotted division is to cut the back of the bulb and let it produce new growing point.
Since a leaf cutting is genetically identical to the parent plant, it should produce exactly the same growing form and coloration, correct?. If it does not, then something else (like a virus) is causing the characteristics in the parent plant.
So to me your argument sounds like evidence to support a conclusion that the plant
is infected with a virus. If a leaf cutting does not display the variegation as it grows new leaves, then it may have been a new leaf that grew faster than the virus was able to spread into it (this is how orchids infected with a virus are treated, getting fresh new meristematic tissue and hoping the virus hasn't yet spread to it).