First Report of Atypical Scab Caused by Venturia asperata on Apple in China

Apple cv. 'Huangtaiping' (Malus pumila Mill.) is grown widely in northern China for the production of jellies, preserves, and cider. In 2018, atypical scab symptoms were observed on fruits Huangtaiping Heilongjiang Province China. The disease incidence was estimated at approximately 0.4%. Symptoms scab-like black spots (3 to 5 mm diam.) distinct from caused by Venturia inaequalis. Conidia generally produced lesions using a modified microscope (Goh 1999), single spore picked up each sample water agar plate with glass needle then transferred PDA amended lactic acid (0.50 ml/L) sulfate streptomycin (0.20 g/L). Fifteen isolates obtained incubated 21°C 6 weeks darkness PDA. colonies gray-black circular morphology floccose texture, which similar characteristics V. asperata described previously (Turan et al. 2019). conidia cylindrical fusiform, 0 1 septate, yellowish 19.7 (13.5 25.8) × 5.7 (3.6 6.9) μm (n = 10) size, larger than ones DNA three randomly selected extracted SDS method (Ping 2004). internal transcribed spacer (ITS) region rDNA amplified primers ITS4/ITS5 (White 1990), sequenced deposited GenBank (MN958665, MN95866 MN958667). BLAST analysis showed that sequences identical had 99.3% sequence identity (AF333447, MT459450 MT459451), 95.4% cerasi (MK810963 MK810964) 94.3% carpophila (MN958609, MN958610 MN958611). addition, complete large subunit ribosomal RNA gene (LSU) LROR/LR5 (Vilgalys Hester (MT845787, MT845788 MT845789). 99.7% (EF114711), 99.2% (MT772296, MT845732 MT845733 ) 98% (MK810848 MK810849). Phylogenetic based concatenated ITS LSU tested grouped strain 2349 same clade closest species carpophila, followed cerasi. July 2019, pathogenicity isolate VAHLJ3-1-1 evaluated Huangtaiping. A suspension concentration 5×105/ml sprayed evenly surface six fruits. order maintain high humidity, inoculated wrapped plastic bag (a cotton ball placed bag) wetness 3 days. Six used as control. Four after inoculation, symptom Huangtaiping, isolated again reisolation frequency 100% isolation, while no control Based morphological molecular identifications, causal agent identified asperata. usually inaequalis (Shen 2020). However, apple has also been Italy France (Caffier 2012; Turan To best our knowledge, this first report associated This information augments knowledge spectrum fruit will be valuable foundation underpinning management strategies cultivar.