Sclerotinia risk live-reporting system for oilseed rape

Project number 2140020105

Lead partner Caroline Young (ADAS)

Start date 01/03/15

End date 31/06/19*

AHDB funding £161,400*

The challenge

Sclerotinia disease, caused by the fungus Sclerotinia sclerotiorum, occurs every year at low levels, but with sporadic serious and economically damaging outbreaks in some years which are difficult to anticipate. It is important to obtain consistently effective control; otherwise even low level disease contributes to the build-up of long-lived inoculum in the soil. Airborne spores result in plant infection when flowering has started and weather conditions are conducive. Foliar fungicide treatments must be applied to prevent infection, before disease symptoms are visible. However, the timing of foliar fungicide applications to prevent infection can be difficult because the period when the crop is at risk of infection is longer than the period of fungicide protection.

Results from a recent research project (LK09130, HGCA 3570) showed that a simple weather-based infection model, using temperature and relative humidity forecasts up to 48 hours ahead, could help to plan and target spray applications. Inclusion of other sclerotinia infection risk factors was also helpful, for example, crop flowering stage, rainfall intensity and spore inoculum estimates. This reflects the complex infection process for S. sclerotiorum in oilseed rape which requires simultaneous occurrence of inoculum, suitable weather conditions and flowering stage. Work is needed to bring together the risk factors and forecasting in a simple format for growers and agronomists to use.

The project

The overall aim of this project is to provide a sclerotinia disease risk reporting system, to help guide fungicide timing, improve control of sclerotinia, and therefore reduce crop losses. This will be achieved by providing forecast alerts and reports of risk factors for sclerotinia infection to growers during the oilseed rape flowering phase. This is to guide the timing of the first fungicide application needed during flowering, and when or if a subsequent application is necessary. This will be done as a ‘live’ reporting system by generating weekly reports which will deliver both forecasting model predictions and information on other disease risk factors based on crop observations (e.g. are there petals sticking to leaves?) and quantification of airborne inoculum, as well as an overall assessment of sclerotinia disease risk. This is different from previous schemes which have only evaluated specific models or risk factors in isolation. The reports will present the data in appropriate simple tables and charts, and interpretation of the in-field and regional results will be provided. Reports will be published on Work will also be done to demonstrate that the forecasting and risk evaluation scheme provides improved control of sclerotinia and gives an economic benefit.

The benefits

The main benefit of the project will be to inform the timing of fungicide applications to give maximum protection against sclerotinia infection. This will result in a reduction of yield losses caused by the disease. In some cases, the impact will also be to enable an informed decision on a second spray, e.g. to justify inclusion or omission of a second spray, or to adjust its timing. If robust control can be obtained with one spray rather than two, this will reduce costs and also minimise the development of fungicide resistance and therefore prolong the availability of effective fungicides. 

*Project extensions

Start Date 01/04/18

End date 31/03/19

AHDB funding £18,894

This project extension will allow forecasting alerts and monitoring reports to continue during the main sclerotinia infection risk periods in 2018.

Start Date 01/03/19

End date 30/06/19

AHDB funding £5,380

Sclerotinia infection risk alerts are now generated via the AHDB WeatherHub. This contract extension covers the provision of commentary. This will highlight any regional weather-based infection risk alerts and ‘near misses’, in context with crop growth stage information. With co-funding and support from BASF, it also provides information on sclerotinia inoculum pressure, based on weekly spore trap (six sites) and petal test data.

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