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Sclerotinia stem rot

Changes in Sclerotinia stem rot climate suitability are likely to create opportunities for broadacre cropping.

Sclerotinia stem rot in NSWThe cropping region of NSW extends along the south-west border of the state and then northwards to Queensland, west of the Great Dividing Range.

Stem rot is a crop disease, primarily caused by Sclerotinia sclerotiorum. It is one of the most non-specific and successful plant pathogens with a host range of over 400 plant species. Stem rot is one of the most serious diseases of broadleaf crops such as canola, chickpea and lupin in Australia, causing high yield losses (up to 24%) when conditions for the disease are favourable. Outbreaks of stem rot are difficult to predict, as the potential for infection is related to combinations of climatic variables including rainfall, humidity, and temperature, as well as previous outbreaks and crop rotations. The key Sclerotinia stem rot life stages include parasitic stage I (infection and germination), parasitic stage II (stem infection) and dormant.

In a survey conducted in NSW in 2020, Sclerotinia diseases were found to be widespread in broadleaf crops and pulses, due to a combination of good crop growth and ideal conditions for the disease. Crops susceptible to Sclerotinia stem rot are grown across inland NSW. The map shows cropping regions where crops which are susceptible to Sclerotinia stem rot are grown in NSW (yellow). Locations indicate sites where sclerotinia is known to occur in NSW. An important example in NSW is canola. Canola production is on the rise, with Australian canola globally sought-after for use as food-grade oil, in biofuel production and for stock feed. Canola is grown in all areas of the NSW cropping zone, with production encompassing central and southern NSW.

What is the NSW DPIRD Climate Vulnerability Assessment? ⏷

Climate change is altering the biosecurity risks for many agricultural commodities across NSW. Primary producers need evidence-based information about the changing climate, and the risks and opportunities it may bring.

The NSW DPIRD Climate Vulnerability Assessments are enhancing the resilience of our primary industries by providing information and data to help the sector better plan for, and respond to, climate change. They have assessed climate change impacts for extensive livestock, broadacre and irrigated cropping, marine fisheries, forestry, horticulture and viticulture, and important biosecurity risks associated with these industries to inform sound planning, risk management and adaptation decisions.

Learn more about the Climate Vulnerability Assessment.

How we assessed climate suitability ⏷

Climate projections were sourced from Climate Change in Australia’s ‘Application Ready Data’. This dataset is comprised of projections from an ensemble of 8 global climate models, each presenting a plausible future climate. Low confidence in the projected changes due to differences between the models is noted in the text. Care should be taken when interpreting these results.

The Climate Vulnerability Assessment is intended to highlight potential industry- or regional-level changes. Intermediate and high emissions scenarios were used in the assessments (RCP4.5 and RCP8.5), but these are not the only future scenarios possible. The inclusion of climate variables important to the commodities production was based on published research, expert knowledge and data quality and availability.

Climate suitability was assessed on a monthly timescale, with the reported climate suitability representing the average for a given month over all years in the dataset. This reflects the pattern of life stages for Sclerotinia stem rot and the need to determine which months are likely to pose the greatest risk to host commodities.

Learn more in the Climate Vulnerability Assessment Project Framework.

Climate impacts: expected challenges for primary industries

Changes in climate suitability are likely across all key life stages of S. sclerotiorum by 2050, under both emission scenarios.

Changes to overall monthly climate suitability for S. sclerotiorum affect Sclerotinia stem rot in NSW in different ways:

  • January and June to November – there are likely to be minimal decreases in climate suitability in the cropping region. The decrease is likely to be greatest under the high emissions scenario (low to high confidence).
  • February to May and December – Climate suitability in the cropping region is expected to remain similar to what has been historically experienced under both emissions scenarios (low to high confidence).

The effects of Sclerotinia stem rot on canola in NSW will depend on:

  • the future distribution of canola,
  • changes in production timings, and
  • the overlap between susceptible life stages of canola and the lifecycle of S. sclerotiorum.

Overall, changes to climate suitability for Sclerotinia stem rot by 2050 are likely to have minimal impacts on NSW's key canola production regions. Decreases in climate suitability during August may allow the canola industry to reduce fungicide treatment during this period. A minimal reduction in climate suitability may occur in some areas, potentially reducing the duration of favourable conditions for disease development and thus reducing the disease’s impact on production. A reduction in disease management and production costs may result. Current strategies to manage the disease are likely to remain effective.

Where can I find the climate suitability maps?

Maps of historical and future climate suitability for commodities were produced to demonstrate where in the state a commodity is likely to thrive or else be limited by future climatic conditions. The maps are not provided on these webpages but can be found in the Climate Vulnerability Assessment Summary Report (PDF, 41425.92 KB).

Summary Report

(PDF, 41425.92 KB)

Related Climate Vulnerability Assessments

Contact us

For more information please email: vulnerability.assessment@dpi.nsw.gov.au