First report of powdery mildew caused by Podosphaera xanthii on Ageratum conyzoides, in Indonesia

Arie Santy Siahaan, Siska
Meeboon, Jamjan
Hidayat, Iman
Kramadibrata, Kartini
Netti Sihaloho, Arvita
Rosenta Purba, Ika

International Journal of Science and Environment
Vol. 6 No. 1 (2026): February 2026 (Indonesia - Jepang - United Kingdom)

Powdery mildew is one of the most common and important fungal diseases and may cause huge economic losses to crop yields worldwide. During survey of powdery mildews in 2011 and 2013, six samples of Ageratum conyzoides were collected from different regions in Indonesia, i.e. Bali, South Sumatera and West Java provinces. Anamorphic features revealed that the fungus belongs to the genus Podosphaera. Two sets of sequences of both ITS rRNA and 28S regions were obtained from the six samples. Phylogenetic analyses, including maximum parsimony (MP) and maximum likelihood (ML) were executed using MEGA7. The strength of internal branches of the resulting trees were tested with bootstrap analysis. Tree scores, including tree length, CI, RI and RC were also calculated. The phylogenetic analysis confirmed that the fungus belongs to the genus Podosphaera, forming a clade with the sequences from Podosphaera xanthii. This is the first report of powdery mildews on Ageratum conyzoides from Indonesia.