Fungicide resistance management in Australian grain crops

Fungicide resistance is a serious and increasing problem in cropping systems worldwide. Fungicides are an important component of integrated disease management strategies for the protection of crops from the impacts of fungal diseases. However, as their use has increased, the effectiveness of some fungicides has been reduced by the development of fungicide resistant pathogen populations. Without intervention, more fungicides are likely to become ineffective

Effect of Austropuccinia psidii inoculum concentration on myrtle rust disease incidence and severity

Austropuccinia psidii (myrtle rust) is one of the most significant threats to plant industries and biodiversity in the Australasian region. Susceptibility phenotypes of Australian native Myrtaceae to A. psidii have varied significantly since the pathogen was first detected in Australia in 2010, with some species appearing to increase in susceptibility over time. We hypothesise that increased inoculum concentrations in natural ecosystems may be contributing to observed changes in susceptibility phenotypes. A study was undertaken to determine the effect of A. psidii inoculum concentration on myrtle rust disease incidence and severity on five native (Rhodamnia rubescens, Syzygium hemilamprum, S. leuhmanii, S. moorei and S. oleosum) and one exotic (S. jambos) species of Myrtaceae under controlled conditions. Disease incidence and severity were found to increase across all species as inoculum concentration increased, with notable increases for species considered to be tolerant or of lower susceptibility to A. psidii. This improved understanding of the influence of increasing inoculum A. psidii concentrations on susceptibility phenotypes can now be integrated with current management and research plans, to predict and mitigate the impact of A. psidii on Australian native biota and ecosystems

Stakeholder survey reveals priorities for African boxthorn biocontrol research in Australia

Insufficient engagement with stakeholders and regulators has been identified as a limiting factor for effective adoption of biocontrol globally. A survey was conducted to engage stakeholders affected by African boxthorn, to ask them about their perceived impacts of the weed and management expectations from biocontrol. Management objectives gleaned from the survey now guide selection and evaluation of candidate biocontrol agents for African boxthorn in Australia. Surveys such as this are an inexpensive way to understand how biocontrol can most effectively intersect with stakeholder perceptions and management priorities, and are likely to facilitate the acceptance and adoption of biocontrol

Combining Inferential and Deductive Approaches to Estimate the Potential Geographical Range of the Invasive Plant Pathogen, <i>Phytophthora ramorum</i>

<div><p><i>Phytophthora ramorum</i>, an invasive plant pathogen of unknown origin, causes considerable and widespread damage in plant industries and natural ecosystems of the USA and Europe. Estimating the potential geographical range of <i>P. ramorum</i> has been complicated by a lack of biological and geographical data with which to calibrate climatic models. Previous attempts to do so, using either invaded range data or surrogate species approaches, have delivered varying results. A simulation model was developed using CLIMEX to estimate the global climate suitability patterns for establishment of <i>P. ramorum</i>. Growth requirements and stress response parameters were derived from ecophysiological laboratory observations and site-level transmission and disease factors related to climate data in the field. Geographical distribution data from the USA (California and Oregon) and Norway were reserved from model-fitting and used to validate the models. The model suggests that the invasion of <i>P. ramorum</i> in both North America and Europe is still in its infancy and that it is presently occupying a small fraction of its potential range. <i>Phytophthora ramorum</i> appears to be climatically suited to large areas of Africa, Australasia and South America, where it could cause biodiversity and economic losses in plant industries and natural ecosystems with susceptible hosts if introduced.</p></div

CLIMEX parameter values used to model eco-climatic suitability of Phytophthora ramorum.

a<p>Expressed as a proportion of soil moisture holding capacity, where 0 =  oven dry and 1 =  field capacity (saturation).</p

<i>Phytophthora ramorum</i> positive streams and models of potential range of the pathogen in the USA.

<p>Stream positive detections in the eastern USA and Washington state are those known at July 2010 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063508#pone.0063508-COMTF2" target="_blank">[60]</a>. As modelled using CLIMEX and the composite model parameters of our model under 1961–1990 climate normals (a); and as generated using a Genetic Algorithm for Rule-set Production (GARP) based on known Californian occurrences and three ecological datasets by Kluza et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063508#pone.0063508-Kluza1" target="_blank">[24]</a> (b).</p

Projected potential distribution of <i>Phytophthora ramorum</i> in Eastern Asia using two different niche-models.

<p>As modelled using CLIMEX and the composite model parameters of our model under 1961–1990 climate normals (a); and as generated using a Genetic Algorithm for Rule-set Production (GARP) based on known Californian occurrences and three ecological datasets by Kluza et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063508#pone.0063508-Kluza1" target="_blank">[24]</a> (b).</p

Global eco-climatic suitability for <i>Phytophthora ramorum</i> under the 1961–1990 climate normals, as modelled using CLIMEX.

<p>Global eco-climatic suitability for <i>Phytophthora ramorum</i> under the 1961–1990 climate normals, as modelled using CLIMEX.</p