Perennial Weed Control

Roundup can be used in the stubbles of all crops to control annual and perennial weeds.

Common Couch

For long-term control of Couch it is essential not to cultivate or disturb rhizomes after harvest.  Broken rhizomes can be buried and lie dormant, missing the spray altogether

  • Take a fork and dig up rhizomes to decide when spraying should commence.  Too often couch is sprayed in September when growth is from the old mother shoot attached to 1-2m of new rhizome leading to poor results.
  • Wait until new rhizomes have come to the surface and produced shoots with 2-3 leaves.
  • Optimum timing is usually late September through October, but spraying can continue until December if Couch is growing, green and healthy.

Onion Couch

Spray Onion Couch at the end of September/ early October when all the bulbils have broken dormancy and produced leaf growth. This means not just shoots on the top 2 bulbils, but shoots from lower down the chain too, as glyphosate will not translocate between bulbils. Where the split dose is being applied, half may be applied in the stubbles. The annual rate should be sufficient for seedlings. Ensure the selective weed control programme applied in crop controls any seedlings, otherwise the infestation will re-emerge.

Volunteer Potatoes

Spray onto at least 6 inches of new growth, from mid September through October, but at least 7 days before the first frost. (Frost will damage the leaves and reduce translocation to the tubers). Leave a minimum of 7 days after spraying before cultivation.

Annual Weed Control

Roundup can be used to control annual weed seedlings on ploughed or cultivated land, on stale seedbeds and also after planting but before crop emergence.

Weeds Considerations Control Strategy
Volunteer Oilseed Rape, Barren Brome, Great Brome, Black-grass, Meadow-grasses, Wild-oats, cereal volunteers These weeds are stimulated to germinate when buried Create a stale seedbed as soon as possible after clearing the field
Serrafalcus family of Bromes (Meadow, Soft and Rye) The seeds from these weeds need to ripen on the surface before they will germinate Leave the field untouched for a month before creating the stale seedbed. This is only an option when later drilling is possible, select varieties accordingly. Use Monitor in the spring to achieve high levels of control

Stale Seedbeds

The technique of creating stale seed-beds is a vital tool in out-of crop control of difficult annual grasses. Stale seedbeds are an integral part of reduced tillage systems.  The Soil Management Initiative produces useful literature.

To encourage the maximum amount of weed germination before drilling and to create a stale seedbed prior to planting spring crops:

  1. Create a medium quality, 5cm clod size, seedbed using a tined cultivator on light soils and heavy disc harrows on medium/heavy soil.
  2. Work top down to conserve moisture. Consolidate with a disc ring press, Cambridge Roll or double disc ring press, depending on soil type.
  3. Wait for weed germination, 10-20 days.
  4. Spray weeds with Roundup.
  5. Drill as early as 6 - 48 hours later depending on the formulation used.

The use of stale seedbeds in conjunction with reduced tillage techniques means that savings in time, labour and cost can be achieved compared to conventional ploughing techniques. Yield increases can be common following the reduced tillage, stale seedbed technique.

Caution: Carrying out reduced tillage techniques without the use of stale seedbeds can result in an increase in annual weed seeds and problems for weed control throughout the rotation

Post-plant pre-emergence

All Roundup formulations have recommendations to spray before crop emergence and have been developed for their ease of tank mixing. This allows residual herbicides to be tank-mixed with Roundup in order to combine residual weed control programmes with the removal of any weeds surviving the cultivation and drilling operations.

Modern Roundup formulations have been developed with improved physical properties, leading to increasingly good compatibility with other herbicides, easier use and quicker cleaning of packaging and equipment.

Cautions: Always Consult the Tank Mix guide to check before mixing any Roundup formulation or contact the Hotline on 01954 717575.

ETA formulations of glyphosate do not mix easily with any other pesticide