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Title: FIRST REPORT OF NEMATOSTOMA ARTEMISIAE ON ARTEMISIA SILVER KING IN THE UNITED STATES

Author
item ROSSMAN, AMY
item TAYLOR, N - OHIO STATE UNIVERSITY

Submitted to: Plant Disease
Publication Type: Research Notes
Publication Acceptance Date: 2/14/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Artemisia 'silver king' is an ornamental plant valued for its silvery white leaves. Plants in Missouri were found to be infected by an unknown fungus that caused the leaves to lose their silvery appearance. This fungus was identified as the loculoascomycete Nematostoma artemisiae. Known previously from Japan and China, this is the fist time that this fungus has been reported from the United States. This disease note will allow plant pathologists to identify the fungus that causes discolored leaves and as a consequence lose of value of this ornamental plant.

Technical Abstract: A fungus associated with leaf hairs of artemisia 'silver king' (Artemisia ludoviciana Nutt. var. albula (Wooton)Keck) from Missouri(Crawford County, near Bourbon) was identified as the loculoascomycete Nematostoma artemisiae Syd. and P. Syd. When the fungus is present, the leaf hairs become discolored and drop off. The living leaves lose their silvery appearance detracting from the ornamental value of the plants. Nematostoma artemisia was described from Japan on Artemisia vulgaris L. var indica (Wall.) Maxim and reported once form China on that host. The type specimen was recently redescribed and illustrated by Sivanesan (1) who provided an account of the genus of which this is the type species. The uniloculate fruiting bodies of N. artemisiae are solitary, superficial to basally immersed, dark brown, globose, 120-160 um diam, with four to ten, black setae 125-175 (300)um long extending from the thickened region around the ostiole. The bitunicate, cylindrical, 8-spored asci are 50-65 x 7-9 um and contain pale brown, broadly fusiform, smooth ascospores, 14-18 x 4.5-5.0 um, three- septate,slightly constricted at each septum. The anamorph pycnidia are similar in appearance to the ascomycete fruiting bodies and contain hyaline, broadly spherical conidia 3-5 um diam. The specimen has been deposited at the U.S. National Fungus Collection (BPI 749199). References:(1) A. Sivanesan. Systema Ascomycetum 6:201,1987.