2008 Annual Report
The bunt fungi in the genus Tilletia are an important but poorly known group of plant pathogens. Research is continuing in collaboration with a scientist at Washington State University to discover, describe, and phylogenetically characterize the bunt fungi on cereal crops in the United States.
Research on canker causing fungi has resulted in several monographic accounts of these genera as well as a number of newly discovered species. A paper on the wood-inhabiting species was published with continuing research in which a number of additional taxa have been discovered. Research to define the genera within this family has been completed. The new generic concepts are based on a classification determined by the analyses of sequences from several genes. The redefined genera include those species related to the type species. In most cases the traditional definition of the genus based on characters of ascospore septation and stromatal features must be altered. New and subtle morphological characters as well as host plant are used to define these genera.
A canker-causing fungus on the related tropical fruit plants, rambutan, and lychee, was identified and reported for the first time from Puerto Rico and Hawaii. Additional plant pathogens on these specialty crops are being identified and characterized.
A new disease of sugarcane caused by an invasive fungus known as orange rust was identified using molecular sequence. However, due to the loss of the permanent scientist studying the systematics of rust fungi, only the most urgent problems concerning rust fungi have been tackled.
This research relates to National Program 303 Plant Diseases, Component I. Disease Diagnosis Detection, Identification and Characterization of Plant Pathogens, a) New Diagnostic Methods and Tools, and b) Detection, Identification, Characterization, and Classification of Pathogens.
Sugarcane is an important crop that is threatened by a number plant diseases caused by fungi. One of these fungi, Puccinia kuehnii is a rust that causes a disease of sugarcane in Asia and Africa; however, until recently, it was not known to occur in the continental United States. It is very similar to Puccinia melanocephala that also causes a disease of sugarcane worldwide, including the United States. This rust fungus, P. kuehnii, is now present in Florida infecting cultivars of sugarcane that were resistant to the other rust fungus. DNA sequences and morphological features were used to identify P. kuehnii and distinguish it from P. melanocephala. This information is used by plant pathologists to identify the rust fungus causing disease on sugarcane as well as by sugarcane breeders and producers to determine which cultivars of sugarcane should be planted. This research relates to National Program 303 Plant Diseases, Component I. Disease Diagnosis Detection, Identification and Characterization of Plant Pathogens, a) New Diagnostic Methods and Tools, and b) Detection, Identification, Characterization, and Classification of Pathogens.2. Two new pathogenic fungi on conifers discovered.
Each year fungi cause billions of dollars damage to agricultural and natural resources in the United States. One kind of fungus causes diseases of conifers trees especially killing the ends of the branches of nursery plants and young trees such as Christmas trees. There has been confusion about the species that cause these diseases. Although considered one species, the fungi on different conifer tree hosts are not all the same. This year it was determined that what has been considered one species is actually three different species that attack different hosts and have a different geographic distribution. These two new species on conifers are described and illustrated and distinguished from the previously known species. This research will be used by forest pathologists to identify the fungi that kill the branch tips and seedlings of conifer trees and to control these diseases. This research relates to National Program 303 Plant Diseases, Component I. Disease Diagnosis Detection, Identification and Characterization of Plant Pathogens, a) New Diagnostic Methods and Tools, and b) Detection, Identification, Characterization, and Classification of Pathogens.3. Fungus causing canker disease of tropical fruit rambutan and lychee new to Hawaii and Puerto Rico.
Rambutan and lychee are tropical plants that produce delicious edible fruits. A fungus that causes a serious canker disease of both rambutan and lychee was discovered for the first time in Hawaii and Puerto Rico. This pathogen was originally described from Malaysia and has been reported from Australia. Knowledge of the identity of this plant pathogen is the first step in developing measures to control this canker disease of these specialty crops. In addition, knowing that this pathogen occurs outside its initial range is useful for plant regulatory and quarantine officials working to control the spread of this disease. This research relates to National Program 303 Plant Diseases, Component I. Disease Diagnosis Detection, Identification and Characterization of Plant Pathogens, a) New Diagnostic Methods and Tools, and b) Detection, Identification, Characterization, and Classification of Pathogens.
5.Significant Activities that Support Special Target Populations
Comstock, J.C., Sood, S.G., Glynn, N.C., Shine, Jr., J.M., Mckemy, J.M., Castlebury, L.A. 2008. First report of Puccinia kuehnii, causal agent of orange rust of sugarcane, in the United States and Western Hemisphere. Plant Disease. 92:175.
Rossman, A.Y., Castlebury, L.A., Farr, D.F., Stanosz, G.R. 2008. Sirococcus conigenus, Sirococcus piceicola, sp. nov. and Sirococcus tsugae sp. nov. on conifers: anamorphic fungi in the Gnomoniaceae, Diaporthales. Forest Pathology. 38:47-60.
Rossman, A.Y., Goenaga, R.J., Keith, L.M. 2007. First report of Dolabra nepheliae on rambutan and litchi in Hawaii and Puerto Rico. Plant Disease. 91:1685.
Mengistu, A., Castlebury, L.A., Smith, J.R., Rossman, A.Y., Reddy, K.N. 2007. Isolates of Diaporthe - Phomopsis from Weeds and Their Effects on Soybeans. Canadian Journal of Plant Pathology. 29(3):283-289.
Mejia, L.C., Castlebury, L.A., Rossman, A.Y., Sogonov, M.V., White, J.F. 2008. Phylogenetic placement and taxonomic review of the genus Cryptosporella and its synonyms Ophiovalsa and Winterella (Gnomoniaceae, Diaporthales). Mycological Research. 112:23-35.
Bobev, S.G., Castlebury, L.A., Rossman, A.Y. 2008. First report of Colletotrichum dracaenophilum on Dracaena sanderiana in Bulgaria. Plant Disease. 92:173.
Phillips-Mora, W., Aime, M.C., Wilkinson, M.J. 2007. Biodiversity and biogeography of the cacao (Theobroma cacao L.) pathogen Moniliophthora roreri in tropical America. Plant Pathology. 56:911-922.
Sogonov, M., Castlebury, L.A., Rossman, A.Y., White, J. 2007. The type of species of Apiognomonia, Apiognomonia veneta, with its Discula anamorph is distinct from Apiognomonia errabunda. Mycological Research. 111:693-709.
Aime, M.C., Rossman, A.Y. 2007. First report of the rust Phragmidium violaceum on Pennsylvania blackberry in California. Plant Disease. 91:1517.
Tsui, C.K., Sivichai, S., Rossman, A.Y., Berbee, M.L. 2008. Tubeufia asiana, the teleomorph of Aquaphila albicans in the Tubeufiaceae, Pleosporales, based on cultural and molecular data. Mycologia. 99:884-894. Vasilyeva, L.N., Rossman, A.Y., Farr, D.F. 2008. New species of the Diaporthales from eastern Asia and eastern North America. Mycologia. 99:916-923.
Rossman, A.Y., Farr, D.F., Akulov, A.Y. 2008. Cosmospora stegonsporii Rossman, Farr & Akulov, sp. nov. Fungal Planet. 23:1-2.
Rossman, A.Y., Farr, D.F., Platas, G., Newcombe, G. 2008. Hydropisphaera fungicola Rossman, Farr & Newcombe, sp. nov. Fungal Planet. 24:1-2.