PT303 Protector® Sclerotinia is the first winter oilseed rape hybrid to offer growers in the UK and Ireland top level yields with built-in tolerance to Sclerotinia.

PT303 has an impressive UK gross output yield on the AHDB Recommended List of 101%. This high gross output is derived from a very high seed yield and a top-level oil content. 

PT303 is the first hybrid to be marketed in the UK with a claim for tolerance to Sclerotinia. This yield sapping disease can reduce yields in commercial situations by up to 30%. Significant yield loss can occur where flowering fungicide applications are missed or delayed - or just in years when sclerotinia pressure is very high. PT303 Protector Sclerotinia can provide extra support for your crop when this unpredictable and highly damaging disease strikes.

Read our article on PT303 and the ever present threat of sclerotinia here to find out how this disease is impacting your OSR crop.

Get £200 cashback with our OSR offer

Corteva Agriscience is helping farmers to maximise the potential of their crops to secure oilseed rape’s valuable position for years to come. This year we will be offering £200 cash back to anyone that purchases Protector® Sclerotinia tolerant hybrid, PT303 and Belkar herbicide for the 2024/25 growing season. Find out more here.


Sclerotinia is a soil-borne fungal pathogen, which can remain viable in the soil for up to 8 years. A single sclerotium produces 10 – 14 apothecia which in turn produce 10 – 14 million spores and it can affect many crops, including: Oilseed rape, Peas, Beans, Lucerne, Carrots and Potatoes (>400 host species).

Sclerotinia is usually the main disease to impact OSR at the important flowering stage and in severe infections the yield impact can be >50%! Although epidemics are uncommon, localised infections occur most years and the inoculum burden continue to build if infections are not controlled. 

There are three main factors required for the infection cycle to take hold in OSR (as illustrated in the graphic below):  

  • Presence of sclerotinia fungal resting bodies (Sclerotia) in the soil which germinate when soils are moist and >10°C
  •  Favourable weather conditions, long periods (>23hrs) of relative humidity >80% & air temperatures >7°C (day & night)
  • Crops to be in flower, providing spores with external nutrients needed for germination

Traditional management of Sclerotinia involves monitoring crop and weather conditions, as well as fungicide strategies, managing susceptible weeds and crop rotation. Timing is key as existing chemical controls are protective not curative! Once you see the infection it is too late and identifying presence of the disease can be done based on the scoring system below. 

Most sprays offer approximately three weeks control; therefore, two sprays are often required to cover most of the flowering period. (Although flowering can last circa 8 weeks). Fungicide efficacy may be limited as new flowers will form during the flowering period that will not be protected by previous applications. 

PT303 has a unique native multi-genic sclerotinia tolerance trait. By sowing PT303 growers can incorporate a level of tolerance to sclerotinia for the first time into their crop management planning. 

Pioneer 2024 WOSR Guide