OSR Stem Extension – Light Leaf Spot Focus!
Posted on 06 February 2026
With many Oilseed Rape crops developing rapidly after favourable autumn conditions, planning stem extension fungicide applications could be vital this spring.
Early spring is a key timing to assess Light Leaf Spot (LLS) risk, particularly in forward crops, to help protect yield and manage canopy structure.
As crops reach mid-calf height, LLS risk increases, highlighting the importance of early monitoring and treatment at the first signs of infection. Canopy Green Area Index (GAI) and local disease pressure should guide treatment decisions.
Control measures:
Fungicides: Early spring stem extension is a critical timing within an integrated disease management programme.
- Prothioconazole‑based fungicides offer strong LLS control.
- Products containing tebuconazole or metconazole can also support disease management while helping regulate crop growth in forward canopies to optimise yield.
Plant Growth Regulators: Plant growth regulators (PGRs) are key for managing forward crops, especially after good autumn growth.
- Clayton Nascar helps create a compact, resilient canopy, reducing lodging and improving crop structure before stem extension.
- Tebuconazole products like Clayton Tebucon 250EW also provide PGR benefits. Though mainly a fungicide, tebuconazole supports canopy tightening in OSR, offering a strong, cost‑effective option that combines growth regulation with disease control.
Read more to find out about control options in our latest technical bulletin below…
