Roundup Use in Autumn
Posted 4 years ago
18/09/2020
Roundup can be used in the stubbles of all crops to control annual and perennial weeds.
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.
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.
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 |
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:
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
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 look at our Tank Mix sheets to check before mixing any Roundup formulation
ETA formulations of glyphosate do not mix easily with any other pesticide