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Candidatus Phytoplasma sp.

Aster yellows phytoplasma


- classification : Eubacteria, Firmicutes, Mollicutes, Acholeplasmatales, Acholeplasmataceae
- this phytoplasma belongs to the group of " Aster yellows "

This phytoplasma is only reported on lettuce (mainly lettuce) in a limited number of countries , mainly in the United States, Canada and Italy. Its damage has been known for many years in several American states (New York, Wisconsin, Oklahoma, Texas ...). They can vary greatly in severity from one region and / or from one year to another. This was the case in Texas during the 1980s, where differences of 5 to 46% of affected plants were observed from one experimental site to another. In other states, severe attacks are reported affecting 100% of plants. We find the same situation in Ontario in Canada.

During the same years, then at the beginning of the 90s, sometimes severe epidemics were reported in Italy, in open fields and sometimes even under shelter, in several regions located in the center and in the south of this country as well as in the Riviera. Italian. In some cases, this phytoplasma was mixed with another phytoplasma responsible for chrysanthemum yellows or with viruses (BWYV, LMV). The phytoplasma is also thought to be present in Germany.

The incidence of this phytoplasma in other salad producing countries is not known. The same is true in France, where attacks by this microorganism have been suspected in the presence of lettuce mainly showing accumulations of latex along the veins of the leaves. The laboratory investigations carried out (electron microscopy, serology, etc.) have never made it possible to highlight any phytoplasma, nor any other microorganism.
Last change : 04/26/21