STEM EXTENSION OILSEED RAPE
With many Oilseed Rape (OSR) crops developing rapidly after favourable autumn conditions, planning a stem extension fungicide application will be important this spring.
As crops begin stem extension, a fungicide may be required to mitigate the increasing risk of Light Leaf Spot (LLS).
The optimum timing is when plants reach mid‑calf height, with priority given to any particularly forward crops. Canopy Green Area Index (GAI) and local disease pressure should guide treatment decisions.
Light Leaf Spot (LLS)
LLS poses a high risk across the UK. Infection can continue to spread through spring from autumn‑established inoculum, affecting leaves, stems, flowers and pods.
Yield losses can reach up to 1 t/ha. Infection levels are expected to be high going into the spring. Treatment should begin as soon as early symptoms are detected (incubation may assist with identification).
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.
Image source ADAS
FUNGICIDES
CLAYTON TUSKAR™
ACTIVE INGREDIENTS 250 g/L prothioconazole
USE RATE & TIMINGS
Emulsifiable Concentrate (EC)
Up to 0.7 L/ha, for a maximum number of 2 treatments per crop at a minimum 14 day spray interval. Latest application 56 days before harvest.
CLAYTON NAVARO™
ACTIVE INGREDIENTS 125 g/L prothioconazole + 125 g/L tebuconazole
USE RATE & TIMINGS
Emulsifiable Concentrate (EC)
Up to 1.0 L/ha, for a maximum number of 2 treatments per crop at a minimum 14 day spray interval. Latest application 56 days before harvest.
CLAYTON TEBUCON 250EW™
ACTIVE INGREDIENTS
USE RATE & TIMINGS
250 g/L tebuconazole Emulsion (Oil in water) (EW)
Maximum total dose of up to 1.0 L/ha between growth stages BBCH 20 and BBCH 69. Latest application end of flowering.
PGR s
CLAYTON NASCAR™
ACTIVE INGREDIENTS 210 g/L mepiquat chloride + 30 g/L metconazole Water Based (WB)
USE RATE & TIMINGS
Spring use: up to 1.4 L/ha, for a maximum number of 1 treatment per crop from GS31 (beginning of stem extension), up to and including GS 59 (yellow bud), to shorten the crop and manipulate canopy structure, reducing the risk of the crop lodging.