Update on Mycosphaerella dearnessii in France
As previously mentioned in Reporting Service 94/087, Mycosphaerella dearnessii (EPPO A2 quarantine pest) has recently been found in France. The disease was discovered at the beginning of 1993 on Pinus attenuata x radiata hybrids , and is only present in the south-west of France (Aquitaine and Midi-Pyr‚n‚es). Symptoms appear mainly on older needles, as yellow spots becoming brownish with a dark centre, the diseased needles then dry and fall. Up till now, in Aquitaine, tree mortalities have been observed on stands of Pinus attenuata x radiata, more than three years old. In 1993-03, the French Plant Protection Service set up an eradication programme. The following actions were taken: identification of Pinus attenuata x radiata stands (150-200 ha) and collection of samples (paying attention also to maritime pine (Pinus pinaster)), complete destruction of plots where contaminated trees are found, 5-year surveys of all sites and their surroundings with collection of samples in spring and autumn, searching for funds to replace destroyed stands. In 1993, the French Plant Protection Service has tested 365 samples in Aquitaine, and 15 in Midi-Pyr‚n‚es. During surveys carried out elsewhere in France, all tested samples (110 samples from 21 different sites) gave negative results. It has been found that all contaminated stands of Pinus attenuata x radiata are located in Aquitaine (except one in Gers), representing 105 ha which are being destroyed. No maritime pine has been found infested, but other species of pines directly in contact with highly infested P. attenuata x radiata showed serious decline or even death. The French Plant Protection Service will continue to make all possible efforts to eradicate this disease.
Lévy, A.; Lafaurie, C. (1994) D‚couverte de Scirrhia acicola - Un nouveau pathogŠne foliaire des pins attenuata x radiata en Aquitaine.
Phytoma - La D‚fense des v‚g‚taux, no. 463, 33-35.