Biology

Privet leaf blotch-associated virus (PrLBaV) was first described in association with yellow blotching of privet (Ligustrum japonicum) in Italy, and it has also been mentioned to affect Fraxinus excelsior (Navarro et al. 2017). The golden flecking of F. pubescens “aucubifolia” (syn. F. pennsylvanica var. “aucubaefolia”) has been already reported by Baur (1907) as a graft-transmissible disease. The “aucubaefolia” varieties of red ash are vegetatively propagated as decorative and valuable ornamental trees. However, they are often less resilient than uninfected ashes exhibiting growth retardation under suboptimal environmental conditions and being less tolerant against heat and drought stresses. Modes of virus transmission apart from grafting to susceptible woody host species (Fraxinus spp. and Ligustrum sp.) are not known yet. Leaf symptoms of PrLBaV infected F. excelsior are usually less prominent than those in F. pennsylvanica var. aucubaefoliae.

White flecking of leaves of PrLBV-infected ornamental red ash variety (F. pennsylvanica var. aucubaefoliae).