Summary

There is essentially a nil tolerance of contamination of Australian export cereal hays with Rathayibacter toxicus, the causative organism of Annual Rye-grass Toxicity (ARGT); since 2005 testing of hays for export has been mandatory.
This project will use the results of a previous RIRDC-funded project (BSC-1A), a project which drew heavily on results from previous RIRDC-funded projects, in particular development of an assay for R. toxicus, and interpolation of weather conditions for sites identified by longitude and latitude from SILO ‘data-drills’. In BSC-1A the distribution and severity of contamination of export hay crops with R. toxicus in SW WA over six years (2000 to 2005) were mapped, resulting in a substantial database, which comprises ca. 44% of samples tested by the DAFWA annually.
A subsample of the data-set was used to predict weather conditions associated with the incidence and severity of R. toxicus contamination of hays. The most significant predictors were: number of false breaks to the season, and average daily maximum temperature, average daily rainfall and average daily potential evapo-transpiration during September. That is, weather conditions that result in a short growing season are likely to increase the severity of R. toxicus contamination, consistent with previous research (reviewed for example by McKay and Ophel (1993) and Finnie (2006)).
The geographic distribution of R. toxicus in export hays is similar to it’s distribution found in a survey of grains in SW WA over 3 harvests (1997 to 1999) (‘Survey levels of diseased ryegrass in Australian grain’ (GRDC, 2000).

Program

Export Fodder

Research Organisation

HAEN Pty Ltd

Objective Summary

To provide advanced warning for cereal hay, cereal grain and livestock producers of the potential risk of incidence of Annual Rye-grass Toxicity (ARGT).