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NPAG Notice New Pest Advisory Group (NPAG) Sawadaea polyfida (Wei) Zheng and Chen: powdery mildew Ascomycetes: Erysiphales Date: September 5, 2014 Highlights: • Detected on a single Japanese maple in Port Washington, New York in 2013. It is not known if this fungus is established. • Sawadaea polyfida could establish in Plant Hardiness Zones 5-10. • Only known to infect Acer species. • There are other known Sawadaea species reported in the United States. Sawadaea polyfida can be identified through morphological characteristics or PCR. • The dense white mycelial mats of powdery mildew fungi are visible on infected leaves. • Infections of S. polyfida can affect Acer leaves, shoots and stems, buds, flowers and developing seeds. • Powdery mildew may cover both upper and lower leaf surfaces, diminishing aesthetic value of infected trees and in some cases causing defoliation. • Acer is a popular genus of shade trees planted in eastern North America, contributing about 14% of sales in the nursery industry. • Raking and removing fallen leaves can help control the spread of powdery mildew fungi. Need for new technology or knowledge: Additional Information • Assess distribution of S. polyfida in New York to determine if this pathogen is established. • Evaluate potential of S. polyfida to be more aggressive or damaging on Acer species than species of Sawadaea already present in the United States • Determine susceptibility of native species of Acer to Sawadaea polyfida • PPQ Operatives- access the full NPAG report at: http://npag.cphst.org/index.cfm • Operatives outside of PPQ please send information requests to [email protected] Tara Holtz, Chair [email protected] (919) 855-7423 USDA/APHIS/PPQ/CPHST/PERAL 1730 Varsity Drive, Suite 300 Raleigh, NC 27606-5202 Cynthia B. Landry, Vice Chair I Betsy Randall-Schadel, Vice Chair II [email protected] Sawadaea polyfida NPAG Notice 20140905.docx Page 1 of 2 Pages
