Presence of European stone fruit yellows (ESFY or 16SrX-B) phytoplasmas inapricots in Austria

A severe decline of apricot trees, present in Austria for several years, ha s recently reached notifiable levels. Initial symptoms on affected trees re semble deficiencies in water and nutrient supplies, expressed as leaf rolli ng, chlorosis and early reddening, leading to sudden dieback during the gro wing season. Small, wilted fruit and dried leaves may also persist during t he autumn. Phytoplasmas belonging to the 16SrX-B subgroup of European stone fruit yellows (ESFY) were identified by nested polymerase chain reaction/r estriction fragment length polymorphism analysis in a high percentage of af fected trees from two different regions of Austria.