2023/12/09 by Chaisse, Eric, Foissac, Xavier, Verdin, Eric +12
#Diagnostic #Dépérissement #Hyalesthes obsoletus #Lavande #Lavandin #Phytoplasme du stolbur #Tolérance #Épidémiologie
paper · doi:10.17180/tjpt-e315
Lavander and lavandin are symbolic crops in south-eastern France, in the region of Haute-Provence, but they have been affected by yellow decline for decades. The etiological agent which is involved in this decline is the stolbur phytoplasm, which is transmitted by the cixiidae Hyalesthes obsoletus. A reliable diagnosis has been developed, and permitted to secure the specification of phytosanitary certified material, according to the specifications “healthy plants”. A large epidemiological survey identified 16 genotypes of the stolbur phytoplasm. The study demonstrated that the epidemics mainly propagated from lavander to lavander. Finally, the study of the mechanism of tolerance showed that lavander and lavandin susceptibility was not correlated with the relation plant - phytoplasm, but more likely with the interaction of the insect with the plant. The insect is present in all cultivated plots, but in very variable densities. AFLP genotyping has also shown that genetic diversity of wild lavanders was quite restricted, and that genetic selection reduced it only a little.