Fighting back against ALS resistance in sugar beet

With resistance to ALS inhibitor herbicides confirmed in a range of common broad-leaved weeds (in particular poppies, chickweed and, to a lesser extent, mayweed), alternative modes of action should be used to target problem weeds in sugar beet.

Speedwell species are also less effectively controlled by the majority of ALS inhibitors and can easily slip through programmes unchecked unless an appropriate mode of action is used.

Metamitron to the rescue

Two of ADAMA’s beet-specific herbicides, Goltix Titan (metamitron 525g/litre + quinmerac 40g/litre SC) and Goltix 70SC (metamitron 700g/litre SC), are ideal for inclusion in ALS stewardship programmes as they both offer good control of the target weeds mentioned above and have an excellent record in terms of crop safety.

Goltix Titan and Goltix 70SC also benefit from being able to be applied at their maximum individual dose rates from the pre-emergence timing (including at the peri-emergence stage).

Targeting common poppy

Goltix Titan is the best option for the control of ALS resistant poppies thanks to its additional active ingredient, quinmerac.

Two suggested programmes for the control of ALS resistant poppy are as follows:

Option A

1. Pre-emergence application of Goltix Titan (2 litres/ha).

…followed by…

• Post-emergence (T1) application of Goltix Titan (1.3 litres/ha) plus any additional actives required e.g. a low dose of Powertwin (200g/litre phenmedipham and 200g/litre. ethofumesate) plus an oil adjuvant

Option B

1. Very early post-emergence application of Goltix Titan (1.5 litres/ha).

…followed by…

• Post-emergence (T2) application of Goltix Titan (1.5 litres/ha) plus any additional active  ingredients required e.g. a low dose of Powertwin (200g/litres phenmedipham and 200g/litre ethofumesate) plus an oil adjuvant.

Mayweed control

Both Goltix 70SC and Goltix Titan provide good control of mayweed species, with the efficacy of typical programmes ranging from 80 to 100%.

However, a single application will not suffice in weed populations with ALS insensitivity. Therefore, to ensure effective control, applications should be continued until weed emergence is complete.

Challenging chickweed

A pre-emergence application of Goltix 70SC will provide a good start to chickweed control.

However, Goltix Titan will provide even better efficacy (approximately +5% better control compared to Goltix 70SC): this is due to the quinmerac in Goltix Titan which will primarily be absorbed via the weed’s root system, but can also be absorbed via foliar contact.

As such, Goltix Titan will also work well as a post-emergence treatment.

For the best results, post-em applications should be made as early as possible (when the weeds are from cotyledon to the two-leaf stage) and when there is adequate soil moisture to support rapid root uptake.

Key pointers for effective weed control in sugar beet

• Use alternative modes of action to target ALS resistant weeds including:
  • Goltix 70SC (metamitron 700g/litre SC)
  • Goltix Titan (metamitron 525 g/litre + quinmerac 40g/litre SC)
  • Powertwin (200g/litre phenmedipham and 200g/litre ethofumesate SC)
• The addition of alternative modes of action is essential in a Conviso Smart programme.
• The best results will be achieved when pre-emergence and post-emergence treatments are applied.
• T1 and T2 are the key timings for the control of the majority of weeds but be prepared to wait until T3 if the weather is not conducive to weed growth earlier in the crop’s development.
• An oil adjuvant must be used to improve the efficacy of SC herbicides.

More information

To find out more about ADAMA’s range of sugar beet herbicides go to https://www.adama.com/uk/en.

Alternatively, contact your regional agronomy manager by calling the ADAMA technical helpline on 01635 876 622 or via email at ukenquiries@adama.com.

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