Binucleate Rhizoctonia AG‐A causing black root rot of strawberry in Albania

Abstract

AbstractStrawberry production in Albania is very important and growing rapidly, while data on strawberry diseases are lacking. In 2022, symptoms of leaf necrosis, root rot, and wilt were observed on strawberry plants of cultivars ‘Savana’, ‘Sabrina’, and ‘Fortuna’ in greenhouses near Vajkan, Fier, Albania. The disease incidence was estimated at 50%. Only isolates of Rhizoctonia spp. were obtained from symptomatic plants. The isolates formed fast‐growing, white colonies with binucleate, typically branching hyphae and no sclerotia, resembling Rhizoctonia AG‐A. BLAST analyses of the ITS rDNA of isolate RhizAl (accession number OR231136) revealed the highest nt homology of 99%–100% (100% query coverage) with binucleate Rhizoctonia AG‐A isolates, while the neighbour‐joining phylogenetic analyses confirmed the identification. The pathogenicity of the isolate RhizAl was demonstrated by inoculations of disease‐free strawberry daughter plants (cv. ‘Fortuna’) that developed mild wilting and leaf necrosis 45 days after inoculation while plants collapsed with root necrosis 60 days after inoculation. In this study, binucleate Rhizoctonia AG‐A was detected for the first time as a causal agent of black root rot of strawberries in Albania and in general, and studies on the general importance of Rhizoctonia spp. in different crops in Albania are needed.