The Recombinant Potato virus Y (PVY) Strain, PVY, Identified in Potato Fields in Victoria, Southeastern Australia.

Potato virus Y (PVY) is one of the main viruses affecting potato in Australia. However, molecular characterization of PVY isolates circulating in potato in different states of Australia has not yet been thoroughly conducted. Only nonrecombinant isolates of three biological PVY strains collected from potato were reported previously from Western Australia and one from Queensland.

Modeling Pathogen DNA Content and Visual Disease Assessment in Seed Tubers to Inform Disease in Potato Progeny Root, Stolon, and Tubers.

Measurement of pathogens on seed tubers is essential for informing likelihood of subsequent potato disease. Here we utilized quantitative PCR assessment of pathogen DNA and visual assessment of disease to measure seed tuber inoculum and used this to model development of disease in potato grown in pathogen-free soil. Analysis by recursive partitioning and modeling using receiver operating curves indicated both abundance of Rhizoctonia solani AG3 and Streptomyces scabies DNA, and disease symptoms associated with these pathogens on seed tubers could predict subsequent disease in progeny tubers and for R.

Genetic characterization of a novel Phomopsis sp., a putative biocontrol agent for Carthamus lanatus.

A large number of isolates of Phomopsis sp. have been collected from the weed Carthamus lanatus (saffron thistle) in Australia, and their potential as biological control agents for weeds of the Asteraceae has been demonstrated. An analysis of their genetic diversity and a multigene phylogenetic analysis were undertaken to ascertain whether these isolates were distinct from other species of Phomopsis that commonly attack crop species in Australia.

Edaphic Soil Levels of Mineral Nutrients, pH, Organic Matter, and Cationic Exchange Capacity in the Geocaulosphere Associated with Potato Common Scab.

ABSTRACT In order to determine possible relationships between geocaulosphere soil properties and severity of common scab of potato caused by Streptomyces scabies, soils were collected from representative commercial potato fields in Canada: in Simcoe and Dufferin Counties, Ontario and across Prince Edward Island (PEI) in August 2004. Soils immediately adjacent to tubers were sampled and analyzed for select edaphic factors and for pathogen presence using polymerase chain reaction (PCR) tests with primers that amplify a region of the TxtA gene involved in regulating the biosynthesis of the thaxtomin toxin family. Individual tubers were assessed visually for scab severity.