Warning: The following pest reports have not yet been confirmed with the appropriate National Plant Protection Organization. They are provided solely as an early warning to NAPPO countries, and all National and Regional Plant Protection Organizations should use this information with caution.

Subject: New host range information for phytoplasmas of quarantine concern to Canada
Publicada: December 20, 2001
Source:
Jarausch, W., B. Jarausch-Wehrheim, J.L. Danet, J.M. Broquaire, F. Dosba, C. Saillard, and M. Garnier. 2001. Detection and identification of European stone fruit yellows and other phytoplasmas in wild plants in the surroundings of apricot chlorotic leaf roll-affected orchards in southern France. European Journal of Plant Pathology Vol. 107:209-217.

Submitted by: Canadian Food Inspection Agency, PHRA Unit, Sciences Division

Background: Leafhopper-vectored phytoplasmas cause numerous and important diseases of crops, woody shrubs and trees. Several of these phytoplasma-associated diseases have not been reported from Canada and are of regulatory concern.

Between 1994 and 1998, field surveys were conducted in southwestern France to identify host plants of the European stone fruit yellows (ESFY) phytoplasma. A total of 431 samples were collected from 51 plant species and were tested for the presence of phytoplasmas by PCR using universal and ESFY-specific primers.

ESFY phytoplasma, which is responsible for diseases such as apricot chlorotic leaf roll, was detected in wild Prunus around affected orchards, as well as in symptomless dog rose bushes (Rosa canina), European ash trees (Fraxinus excelsior), and a declining European hackberry (Celtis australis). These results show that wild Prunus species and other hosts may represent an important reservoir for the phytoplasma and may be the starting point for new infections in orchards planted with healthy material. The presence of rubus stunt (RS) phytoplasma in great mallow (Malva sylvestris), dog rose, and Rubus ulmifolius Schott was also demonstrated for the first time. In addition, a previously undescribed phytoplasma type belonging to the stolbur phytoplasma group was detected in symptomless red dogwood (Cornus sanguinea). It has been designated COR and appears to occur in the same areas where grapevine is also commonly infected by the stolbur phytoplasma inducing bois noir.

This situation is considered significant for an alert because (i) phytoplasma-associated diseases such as Apricot chlorotic leaf roll, rubus stunt, and bois noir are considered or regulatory concern to Canada, and (ii) this survey provides new information concerning potential hosts and therefore possible pathways for these quarantine pests.