Clayton Gatso EC™, Stewardship Guidelines for Oilseed Rape 2026

Permissible Tank Mixing

• Tank mixing with an insecticide for CSFB control is permissible if required.
• The addition of a non-wetted water conditioner (that has no built-in adjuvant) will improve efficacy in hard water areas and is strongly recommended.
• Tank mixtures with propyzamide can now be permitted and can also be additionally useful for grass weed resistance management purposes.

Prohibited Tank Mixes

• Clayton Gatso EC does not require the addition of any adjuvant.
• Avoid any other chemical application within 14 days before or after an application of Clayton Gatso EC. Allow at least 14 days between Clayton Gatso EC and other herbicides.

Timing Restrictions

• From 4 true leaves of the oilseed rape crop.
• Do not apply after the 15th October or the 6 true leaf stage, whichever is sooner.
• No Spring applications.
• No Spray Period
• A 10-day no spray period must be in place before application of Clayton Gatso EC.
• A 14-day no spray period must be in place after application of Clayton Gatso EC for other chemical applications.
• After 7 days, application of crop nutrition products and insecticides is permissible.

Condition Prohibition

• Do not apply in cold weather, especially when frosts may occur and temperatures should be above 7°C . Do not spray if frost is expected or immediately following frosty weather. The optimum spraying temperature is 8–25°C, with optimum air moisture above 65%.
• Ensure the crop is showing no crop stress or signs of pest damage.
• Do not apply to crops suffering stress from frost, pest or disease attack, previous herbicide treatments or low vigour.
• Ensuring adequate crop waxing and sufficient crop nutrition will also minimise risk.

Best Practice

• Apply Clayton Gatso at 1.0 L/ha in 200–400 L/ha of water in a minimum of 150 L of water to ensure good uptake.
• Use drift-reducing nozzles and apply in good spraying conditions, with a suitable forward speed to ensure good crop coverage. Apply as a FINE or MEDIUM spray as defined by BCPC. A water conditioner can aid application.
• Ensure Blackgrass has reached 3 fully expanded leaves and is actively growing. The optimum timing for annual grass weeds is from 3 leaves to the beginning of tillering. For optimum efficacy, weeds must be well covered.
• Avoid overlapping sprays to reduce the risk of crop damage.
• In the event of crop failure following a treatment with Clayton Gatso, ensure any survivors are over-sprayed with glyphosate prior to sowing the next crop.
• Following treatment, broad-leaved crops may be sown at any time. Allow at least four weeks before sowing wheat, barley or maize and cultivate the soil thoroughly to a minimum depth of 20 cm before sowing.

Resistance Management

• Strains of some annual grasses (eg Blackgrass, Wild Oats, and Italian Ryegrass) have developed resistance to herbicides, which may lead to poor control.
• A strategy for preventing and managing such resistance should be adopted.
• Guidelines have been produced by the Weed Resistance Action Group (WRAC) which should be referred to.
• This product contains clethodim which is an ACCase inhibitor, also classified by the Herbicide Resistance Action Committee as ‘Group 1’. Use only as part of a resistance management strategy that includes cultural methods of control and does not use ACCase inhibitors as the sole chemical method of grass-weed control.
• It is recommended to adopt a long-term strategy integrating cultural and chemical measures.

The following are the key elements of the resistance management strategy:

• Always follow WRAG guidelines for preventing and managing herbicide-resistant weeds.
• Maximise the use of cultural control measures wherever possible (e.g. crop rotation, ploughing, delayed drilling etc.)
• For effective resistance management, use tank mixes or sequences of effective herbicides with different modes of action within individual crops, or successive crops.
• To reduce the risk of developing resistance, applications of Clayton Gatso should be made to young, actively growing weeds.
• Monitor fields regularly and investigate the reasons for any poor control.
• Do not use reduced doses of Clayton Gatso EC on grass weeds where resistance is suspected.