Three collections of crown rust (Puccinia coronata), from Czechoslovakia, West Germany and the U.K., were tested for their pathogenicity on sixteen cultivars of perennial ryegrass. The Czechoslovakian collection had the highest level of infection on twelve of the cultivars, although with most cultivars there were no significant differences in infection levels. Three cultivars, although with most cultivars there were no significant differences in infection levels. Three cultivars, Kerem, Loret, ta and Tando, contained qualitative resistance to crown rust which was overcome by the Czechoslovakian collection, although they retained a moderately high level of background resistance to this collection.

After the first detection of myrtle rust (Austropuccinia psidii) on mainland New Zealand in May 2017, the Ministry for Primary Industries sought information about how weather conditions would affect regional and seasonal risk of disease establishment to help plan the incursion response. Using internationally published information, a pathogen-process model was developed to predict infection, latent period and sporulation in relation to weather variables (temperature, relative humidity and solar radiation). This Myrtle Rust Process Model (MRPM) was implemented by the National Institute of Water and Atmospheric Research Limited using numerical weather model data to produce weekly maps of potential risk. Predicted risk was greatest in northern North Island and decreased further south, but was still substantial in coastal areas of the north-western South Island during summer and autumn. Risk was low in southern coastal areas of the South Island and the lowest risk occurred in mountainous areas, particularly in the South Island. Retrospective analysis of surveillance data showed that the MRPM accurately predicted geographic risk and it is currently in use for tactical planning of incursion surveillance and organism management.

Bacterial pathogens of Gramineae principally belong to the genera Clavibacter, Erwinia, Pseudomonas and Xanthomonas, the last being the most important. A general survey of these pathogens is given, with details on nomenclature, symptoms, natural host range, geographical distribution and potential quarantine significance for the EPPO region. The status of Xanthomonas campestris pathovars with overlapping broad and narrow host ranges on Gramineae is discussed. It is proposed to adopt a broad concept of X. campestris pv. translucens and evaluate it as a potential quarantine hazard for the EPPO region.

False flax (Camelina sativa L.) plants were found to be infected with a yellows-type disease caused by a phytoplasma in experimental plots at the Edmonton Research station. Alberta, Canada. Typical phytoplasmas were detected in the phloem cells in ultrathin sections from leaf midrib tissues examined by electron microscopy. These observations were supported by polymerase chain reaction (PCR) using two primer pairs, R16 F2n/R2 and R16(1)F1/R1, derived from phytoplasma rDNA sequences. Aster yellows (AY) and potato witches'-broom (PWB) phytoplasma DNA samples served as controls and were used to study group relatedness. In a direct PCR assay, DNA amplification with universal primer pair R16F2n/R2 gave the expected PCR products of 1.2 kb. Based on a nested-PCR assay using the latter PCR products as templates, and a specific primer pair, R16(1)F1/R1, designed on the basis of AY phytoplasma rDNA sequences, a PCR product of 1.1 kb was obtained from each phytoplasma-infected false flax and AY sample, but not from PWB phytoplasma and healthy controls. DNA amplification with specific primer pair R16(1)F1/R1 and restriction fragment length polymorphism indicated the presence of AY phytoplasma in the infected false flax sample. This is the first reported characterization of AY phytoplasma in false flax.

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