8th INTERNATIONAL WHEAT CONFERENCE

The BIoLogy ANd ePIdemIoLogy of STRIPe (yeLLoW)
RuST IN AuSTRALIA – The BASIS foR A NATIoNAL INTegRATed
dISeASe CoNTRoL STRATegy
C.R. Wellings
Industry & Investment NSW, seconded to The University of Sydney, Plant Breeding Institute,
Private Bag 4011, Narellan, NSW 2567
E-mail Address of presenting author: colin.wellings@sydney.edu.au
The wheat stripe (yellow) rust pathogen, Puccinia striiformis f. sp. tritici (Pst), was first
recorded in Australia in 1979 and became endemic to the eastern Australian wheat zone
causing serious losses in the mid 1980s. Concerted pathology and breeding research and
development combined with industry adoption of resistant varieties resulted in minimal
losses for nearly 20 years. The first report of stripe rust in Western Australia in 2002
was the result of a new foreign pathotype incursion. This aggressive pathotype widened
its distribution in following years to encompass the entire Australian wheat production
zone, and caused serious losses recently estimated at $AUD 127 million each year. In addition,
annual increases in production costs due to fungicide purchases have ranged from
$AUD 40-90 million. Stripe
Over the past 30 years, the pathogen has become progressively adapted to the Australian
environment. Distinct biological forms of the pathogen have been identified and the
relative threat of particular forma speciales to host groups of economic importance has
been determined. Continued monitoring of the pathogen population has demonstrated
the role of mutation and selection in driving pathotype evolution. Selection of resistant
varieties, and characterizing the resistance genotype and phenotype of these varieties, has
been important in monitoring the efficacy of genes relevant to the local industry.
The dynamics of host resistance and pathogen variability requires a close connection between
extension and research staff in order to maximize the available resources of host
resistance and fungicide availability. This paper presents details of epidemic development
of Pst under Australian conditions, the interplay of variety resistance and pathogen population
dynamics, and the strategic use of fungicides. These strategies need to be developed
and applied in an Australian dryland wheat production context that is characterised by
relatively low yield, driven by concerns for minimising risks associate with variable input
costs, and the need to capture maximum yields in favourable seasons.
The paper describes the methods and outcomes of a national R&D program that aims to
deliver practical management options to minimise the impact of wheat stripe rust – currently
considered the most potentially damaging foliar disease of wheat in Australia with
a capacity to inflict losses approaching $AUD 1 billion if left unchecked.
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