Tall verbena (Verbena bonariensis) is widely used in landscape layout in sparse forests, botanical gardens and villa areas, and it is also a kind of Chinese herbal medicine. The flower and bud use as Chinese herbal medicine causing heat-clearing and detoxification. In August 2019, observed on tall verbena in Shangqiu, Henan Province, China. Symptoms white fungal growth observed on both sides of fresh and mature leaves of tall verbena grown on campus at Shangqiu Normal University. More than 60% plants were infected by this fungus and infected plants were observed to shed leaves early. One representative voucher specimen was deposited at the herbarium of Shangqiu Normal University (SQNU), Shangqiu, China, under the accession number of Vb01. Conidiophores of the fungus contained 5-6cells and measured 102.0-142.9μm (mean 126.2μm, n = 30) long, with foot-cells of conidiophores measured 36.5-46.9μm (mean 42.9μm, n = 30). Conidia produced in chains were variable in shape, ellipsoid to ovoid, and measured 24.8-30.7×12.0-17.9 μm (mean 27.35×15.08μm, n = 50), with a length/width ratio of 1.4 to 2.3. Fibrosin bodies were observed in the conidia. No chasmothecia were found. The morphological characteristics were consistent with the genus Podosphaera. To identify above powdery mildew fungus at species level using molecular markers, the complete ITS region of rDNA from the representative specimen was amplified with universal primer pair ITS1/ITS4 and directly sequenced. The resulting sequence of 567 bp was deposited in GenBank (Accession No. MT864007). A BLAST search of this sequence showed more than 99% sequence identity with P. xanthii isolates (AB046985, AB462804, AB936277 and KM260741) on various hosts (Hirata T, 2000; Meeboon, J., and Takamatsu, S. 2015; Tam L. T. T. 2016). Phylogenetic analysis revealed that ITS sequence from Vb01 isolate was grouped into a clade with P. xanthii s. lat.. A pathogenicity test was conducted through inoculation by gently pressing a diseased leaf onto five healthy leaves of a potted tall verbena. Five non-inoculated seedlings were used as controls. The plants were maintained in a greenhouse at 26 to 28 ℃, and relative humidity of 60 to 65%. Inoculated leaves developed symptoms after nine days, whereas the control plants remained symptomless. The fungus presented on the inoculated plant was morphologically identical to that originally observed on diseased plants, fulfilling Koch's postulates. P. xanthii s. lat. has been reported on several hosts in China (Braun & Cook, 2012). This is the first report of P. xanthii s. lat. on Verbena bonariensis outside of Japan (Meboon, 2015).