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Sclerotinia infection surges in Kwinana port zone, DPIRD research shows 

Sclerotes on narrow leaf at Mingenew

Project name and code 

  • Sclerotinia management for narrow leaf lupin crops in Western Australian farming systems. Grains Development Research Commission (GRDC) Code: DAW2104-002RTX
  • Disease surveillance and related diagnostics for the Australian grains industry (Western region). Grains Development Research Commission (GRDC) Code: DAW2104-003RTX 

Number of infected paddocks rises each year    

Research conducted by the Department of Primary Industries and Regional Development (DPIRD) has found sclerotinia incidence is steadily increasing in lupin crops grown in the Kwinana port zone. 

Findings from 2022 in Kwinana north, found sclerotinia affected 92 per cent of paddocks surveyed, whereas in 2021 it was 60 per cent.  

In Kwinana south, 67 per cent of paddocks surveyed had either canopy or basal sclerotinia, a significant increase when compared to the year prior when no cases were recorded in surveys.  

The biggest jump, however, was recorded in the east zone, where 100 per cent of the paddocks surveyed had sclerotinia in 2022. In 2021 it was only 17 per cent. 

Sclerotinia remains an ongoing significant issue for growers in the Geraldton port zone, the research found sclerotinia was present in 14 out of 15 paddocks surveyed in 2022 and was similar in 2021.  

Field trials and yield impact 

In trials, sclerotinia incidence in the canopy was significantly lower than in 2021 trials, likely due to the dry period in May/June. 

This delayed the start of the sclerotinia lifecycle and many crops were April sown in 2022, so flowered early and escaped infection.  

Five out of 15 trials in the Geraldton port zone trials had less than 35 per cent infection, and researchers found that disease occurred later in the growing season than in 2021, promoted by the wet spring.  

The incidence of basal infection was low across all port zones.  

In most trials this allowed for data to be gathered on canopy infection management in the absence of significant basal infection.  

Of the trials where fungicide was applied, there was a yield response to foliar fungicide application in 5 out of 13 trials. 

Yield responses ranged from 7-50 per cent and were generally found in trials where sclerotinia incidence was significant (eg 30 per cent or more plants infected) and other diseases were present eg anthracnose, phomopsis, or brown spot.  

The greatest response (50 per cent) was in Amira albus lupin infected with severe anthracnose.  

In two out of five trials that had a fungicide response, the latest timing fungicide application (usually during flowering/podding of branches) proved to be the most effective as it provided protection of the crop into spring when sclerotinia was particularly active in 2022.  

In two other trials, the species was albus which is more likely to give a yield response to fungicide due to vulnerability to anthracnose infection, which fungicide application at flowering / podding can also reduce.   

What is working to combat lupin sclerotinia 

Lessons gained in research conducted in 2021 and 2022 are assisting lupin growers and agronomists in making decisions about which parts of lupin paddocks to focus sclerotinia management strategies on and which growing seasons are higher sclerotinia risk.  

Sclerotinia risk has been found to be higher in lupin crops grown in paddocks that have a previous history of the disease, high plant density, loamy soil type, early canopy closure and good yield potential.  

Favourable rainfall, humidity and temperature conditions are required at all stages of the disease lifecycle for it to initiate, persist and spread.  

Foliar fungicide application during crop flowering – early pod emergence on the main spike has been found to significantly reduce canopy infection.  

It is more likely to be profitable if application precedes or coincides with favourable weather conditions (humid/wet weather with temperatures 16-25°C).  

A wet spring will increase the chances of obtaining a yield response from fungicide application for sclerotinia.   

Crops in 2022 were generally very high yielding in all port zones due to the long spring, allowing additional higher order branch pods to form and fill.  

The wet spring was also favourable for sclerotinia and other lupin diseases in the Geraldton and Kwinana port zones so fungicide applications (particularly those applied later in the season to protect branch pods) were more likely to be profitable.   

Contamination in grain by sclerotia (survival bodies of the pathogen) was found in most Geraldton port zone trials and the Kwinana port zone trial but was only significantly reduced by fungicide in one out of the eight trials where fungicide was applied.  

There were trends for reduction in grain contamination in two grower scale trials but with limited grain samples these weren’t statistically significant.  

Research in 2023 is investigating some potential strategies to reduce germination of sclerotia which is of great interest to growers in their efforts to manage the disease. 

Prevention is key  

Research from 2021 and 2022 has culminated in production of a new GRDC farmnote which assists lupin growers to assess their lupin sclerotinia risk paddock by paddock.  

It is crucial that growers particularly consider previous paddock rotations and sclerotinia history when sowing lupins.  

Growing canola, which is vulnerable to infection, in close rotation with lupin, increases sclerotinia risk.  

Currently, research is evaluating wider row spacings and lower seeding rates as well as fungicide strategies for reducing sclerotinia risk in small plot and in paddock scale trials in conjunction with lupin growers.  

Disease management practices are currently limited and economic responses vary.  

In paddocks deemed high risk for infection, growers are encouraged to consider applying a single registered foliar fungicide during main spike flowering to early pod emergence, to protect stems and branches from canopy infection.  

The challenges are that application should occur before symptoms are seen, as infection can develop extremely rapidly within weeks under favorable weather conditions and be difficult to control. 

Further information

Understanding and managing sclerotinia stem rot in lupins DPIRD article
GRDC Fact sheet

Contact  

Ciara Beard
DPIRD Research Scientist 
E: Ciara.Beard@dpird.wa.gov.au
P: (08) 9956 8504