Submitted to: Mycological International Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/24/2002
Publication Date: 8/15/2002
Citation: Hernandez, J.R., Palm, M.E., Castlebury, L.A. 2002. PUCCINIA HEMEROCALLIDIS, CAUSE OF DAYLILY RUST, A NEWLY INTRODUCED DISEASE IN THE AMERICAS. Mycological International Conference Proceedings.
Technical Abstract: Daylilies (Hemerocallis spp.) are the most important perennial flowering plant grown in the U.S. and are traded extensively by hobbyists. A rust of daylilies was introduced recently into North and Central America. Puccinia hemerocallidis is known on daylilies in Asia (stages II, III) with Patrinia (Valerianaceae) as the alternate host (stages 0, I), also native to Asia. Specimens from Costa Rica, Japan, Russia and the United States as well as previously collected specimens from its native eastern Asia were examined morphologically to confirm that this rust was P. hemerocallidis. In addition, the ITS region of the ribosomal DNA was sequenced from six representative fresh specimens from the Americas and Asia. The range of variability of certain morphological characteristics, including the ratio of non-septate to 1-septate teliospores, was greater than indicated in the current literature. Teliospore and urediniospore sizes varied among specimens but statistical analysis indicated that there was no significant difference in size between the Asian and the American spores. Three synapomorphies (including one indel) were present in the ITS region that distinguished the two Asian specimens from the four American specimens. However the ITS variation within the American or Asian specimens was approximately equal to variation between specimens from the two broad geographic areas. We conclude that the rust introduced into the Americas is Puccinia hemerocallidis.