Autumn Disease Control in Winter Oilseed Rape!

Protect crop establishment with effective early disease control.

Getting the crop in and away with a healthy, well-structured autumn canopy is essential for supporting root development, improving crop resilience and protecting oilseed rape through the critical establishment and overwintering period.

Problem diseases to watch out for in the autumn… 

Phoma leaf spot

For the best start, monitor crops closely for Phoma and Light leaf spot throughout the autumn period, and where spray thresholds are reached, treat with broad-spectrum protective and systemic fungicides (with either straight or co-formulated product options) where required. 

Phoma spray threshold: 10-20% of plants infected; use lower threshold on more susceptible varieties and/ or where plants are small. 

Disease management to control damaging diseases in the autumn is vital: 

Light Leaf Spot can lead to yield losses of up to 1.0 t/ha if left unchecked. Early prevention is key, as infection often begins in autumn but symptoms can be delayed. 

Phoma infection typically causes yield reductions of 0.5t/ha in susceptible varieties. Early leaf spotting is the first warning sign. 

AHDB data shows average yield responses to a two-spray autumn fungicide programme at 0.3t/ha. 

Light leaf spot should be prevented from developing early. 

Good protection from subsequent disease development will be provided by a protective application of prothioconazole or tebuconazole in autumn/winter after GS20 (usually late October to early December). 

Follow up spray(s) with an alternative product may be required in the spring from stem elongation, depending on disease development. 

A protective application of prothioconazole or tebuconazole in autumn or winter after GS20, usually from late October to early December, will help protect against subsequent light leaf spot development. Follow-up spray(s) with an alternative product may be required from stem elongation in spring, depending on disease development.

Light leaf spot threshold:  Treat as soon as infection is seen. To confirm disease, incubate the leaves.

Phoma leaf spot/Stem canker can be found from October onwards. Best control of stem canker is usually achieved from an autumn application (after GS 20) of prothioconazole or tebuconazole-based products applied at the first sign of disease. 

A repeat application of an alternative effective product in late autumn/winter may be required if symptoms reoccur. 

Fungicides for cost-effective disease control in OSR this season

Products listed below are tailored to provide effective disease control, flexibility in application, and added benefits such as growth regulation in forward crops. 

Whether used as part of a one- or two-spray programme, Clayton’s fungicide options support growers in achieving robust autumn disease control and setting up the crop for strong spring performance. 

Clayton Navaro™ & Clayton Pontoon™ | 125 g/L prothioconazole & 125 g/L tebuconazole

• Disease control and growth regulator in one can. 
• Dual-active co-formulation. 
• Targeting damaging Light leaf spot and Phoma. 
• Additional beneficial growth regulatory effect on forward crops. 

Clayton Trellis™ & Clayton FInch™  | 160 g/L prothioconazole and 80 g/L tebuconazole.

• Powerful solution for both Phoma and Light leaf spot control. 
• EC formulation. 
• Proven approach to autumn OSR disease management. 
• Added convenience of a one-can solution, for cost-effective, rounded protection. 

Clayton Tuskar™  | 250 g/L prothioconazole

• Powerful systemic, protectant and curative fungicide for wide disease control options. 
• Targeting damaging Light leaf spot and Phoma. 
• Flexible tank-mix compatibility with other autumn actives. 

Clayton Tebucon 250EW™ & Clayton Tebbit™ | 250 g/L tebuconazole

• High-loaded, straight tebuconazole formulation. 
• Cost-effective disease control option. 
• Beneficial growth regulatory effect on forward crops. 

Best practice for autumn fungicide applications

• Assess crops regularly from emergence onwards.
• Monitor local disease forecasts.
• Apply fungicides promptly once spray thresholds are reached.
• Match product choice to disease pressure, crop development and variety susceptibility.
• Consider the additional growth-regulating benefits of suitable fungicides on forward crops.
• Continue monitoring throughout winter and always consult the product label and application rates.