Submitted to: XII Biennial Workshop on Smut Fungi Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/15/2000
Publication Date: 8/15/2000
Interpretive Summary: Knowledge of the occurrence of bunt fungi on grass crops such as wheat, rice, and millet around the world is extremely important for the risk-free export and import of these commodities throughout the world. Presence of a previously unknown species of bunt fungus in the United States recently caused a plant quarantine crisis in the export of wheat from that country. The newly described species is now known from both the United States and Australia. Yet, new species of bunt fungi are still being discovered. This paper reports on a new species of bunt fungus on ryegrass found originally in a shipment that was being sent from Australia to Oregon and then found in Australia. The new species is compared with other similar looking bunt fungi. This paper will be used by wheat pathologists and plant quarantine officials to identify bunt fungi found in shipments of wheat and rice crops as well as in developing plant quarantine regulations concerning these grass crop commodities.
Technical Abstract: In 1997, the first author found two fully bunted seeds in two different samples of perennial ryegrass from Australia that had been sent to the Oregon Department of Agriculture's Seed Testing Laboratory. The bunted seeds were filled with pale to dark brown, irregularly reticulate teliospores. No similar smut has been reported on Lolium in Australia. During a study of Australian smut fungi on Lolium perenne in 1999, the authors found the reticulate-spored bunt to be widely distributed but at low levels in seed samples from New South Wales and adjacent states. Further study of the Australian Lolium smut showed that it represents a previously undescribed species. Information on teliospore germination, morphological features, infectivity and relatedness to other Tilletia spp. is presented herein. A preliminary report on this Lolium smut was published (Carris, 1998), and information on its incidence and distribution in Australia are included in a report by Carris and Castlebury in these proceedings.