Based on the active ingredient clethodim, the graminicide Centurion MAX has received UK registration and is described as an important and exceptional herbicide to reach the market. Dr. Stephen Moss of Rothamsted Research, a renowned expert in weed control, particularly black-grass, says “It’s great to see a new herbicide that gives effective control of resistant black-grass in oilseed rape.”
Dr. David Stormonth of Interfarm explains that Centurion MAX is recommended for the control of black-grass, annual meadow-grass, wheat volunteers and barley volunteers in winter oilseed rape and sugar beet. “One of the special attributes of Centurion MAX is that although it is an ACCase inhibitor product, it is active on strains of black-grass that are resistant to other ACCase products. In a paper given at the Crop Protection in Southern Britain conference, Dr. Moss reported on six field trials with clethodim in rape where it gave significantly better levels of control of black-grass than tepraloxydim (Aramo), even though the black-grass populations were known to show resistance to this group of herbicides. He concluded that the results indicate that of this herbicide group, clethodim could make a significant contribution to UK growers of oilseed rape.”
He explains that Centurion MAX is unusual in that it is less affected by target site resistance than other ACCase inhibiting herbicides because an additional mutation in the binding site is required. “A worldwide research review considered clethodim to be the lowest resistant risk ACCase inhibiting herbicide, with only two of the 11 known target site mutations conferring high resistance to it.”
However David points out that Centurion MAX must be used wisely in a black-grass control strategy. “For example, in oilseed rape it will be extremely important to use it in a programme with herbicides with different modes of action such as propyzamide or carbetamide. Such products should be used either in mix or after Centurion MAX. This way any survivors from a clethodim treatment should be removed by the other herbicide, thus preventing or reducing any seed return.”
Dr Stormonth says that that the recommended dose rate is 1 litre per hectare. “This is the effective dose for Centurion MAX, regardless of target weed.”
With regard to timing of Centurion MAX, it can be applied from the 4 true leaf stage of winter oilseed rape crop. It will control black-grass and cereal volunteers from the 3 leaf stage to 5 tillers, with annual meadow-grass from 3 leaves to tillering. “In practical terms it should be the black-grass stage which governs the application timing, with 3 leaves being the best timing for Centurion MAX. This is normally when oilseed rape has 4 leaves. Only one application per crop is permitted.”
David Stormonth concludes that it has not been easy to get registration for a new ACCase product in the UK. “Proving useful activity on current UK populations of black-grass was a major focus and took up much resource. Clethodim is known globally to be perhaps the most active of this group. It is unlikely that a better ACCase compound will appear, especially for the UK where there is a history of rapid failure on black-grass. All the more reason to make sure that Centurion MAX is used carefully and strategically in a planned programme to ensure its working life span is maximised.”
Centurion MAX contains 120g/L clethodim formulated as an emulsifiable concentrate and packed in a 5L container. It recommended for use post-emergence in winter oilseed rape and sugar beet to control black-grass, annual meadow-grass, cereal volunteers. It is applied at a dose rate of 1 L/ha in 200-400 litres of water and at a fine or medium spray quality. In winter oilseed rape it can be applied from the 4 true leaf stage and in sugar beet from cotyledon stage. One application can be applied per crop and the latest time of application in oilseed rape is before stem elongation and in sugar beet before row closure. Centurion MAX has no LERAP.
