The graminicide Centurion MAX was launched last autumn and the vast majority of users have been thrilled with the excellent level of black-grass control achieved in winter oilseed rape. With one autumn, and a difficult one at that, under its belt, Interfarm is taking the opportunity to assess the pros and cons and is consequently issuing new guidelines so that growers can get the very best from this exceptional chemical.
“We have had many reports of excellent weed control from early applications of Centurion MAX in rape. There is no question that it works well, better than other contact graminicides, but we have also learnt some lessons in its first year of commercial usage which we want to share with growers. The label hasn’t changed at all, but our guidelines take into account our wider experiences with this chemical,” says Simon Bishop of Interfarm UK Ltd.
“The first lesson is that Centurion MAX should not be tank-mixed with any other chemical this year. When it comes to fungicides, we are not supporting this mix as quite a few of the autumn-applied triazole fungicides have plant growth regulating activity, which can also affect grass-weeds. Nor are we supporting adjuvants or water conditioners as the product is already formulated to give maximum control. Any additional wetting can produce negative side results.” says Simon.
“The second lesson is that we are advising, as a precaution, that Centurion MAX should not be applied after the end of October. After this time, we would anticipate colder weather; with mean temperatures below 7ºC and this means that weeds would no longer be actively growing. Centurion MAX should not be applied immediately after a period of frosty weather, as this could reduce its uptake and translocation in the weed. Any situation where target weeds or crop are under stress e.g. drought, frost, waterlogging or other environmental conditions could interfere with the herbicide’s activity and crop safety.”
Simon also points out that the new guidelines advise a minimum 14 day interval between Centurion MAX and any other chemical, either before or after application. “In particular no dim herbicides are advised to be used in the programme and the crop should have a good wax layer and good nutrition.”
Simon also advises growers and advisors to integrate Centurion MAX into a programme, which includes herbicides with different modes of action. “You can sequence Centurion MAX with propyzamide (Kerb), propyzamide + aminopyralid (ASTROKerb) or carbetamide (Crawler). It is important that clethodim is not the last herbicide treatment in the programme and it should be followed by either Kerb or ASTROKerb. Any survivors from a clethodim treatment will then be controlled by the other herbicide, so preventing or reducing weed seed return. This would help minimise or prevent the selection and development of resistant weed strains.”
He points out that the Centurion MAX label says that it should be applied when black-grass has 3 leaves. “This fits in as Centurion MAX is unlikely to be the first graminicide used. This would normally be one applied much earlier for the control of cereal volunteers. Because Centurion MAX is the best “dim” across all strains of black-grass, it should be saved for the more difficult to control weeds. Only one application of Centurion MAX is permitted in each crop, but growers are able to use two different ACCase herbicides, a fop in this case, provided they are targeted at different weeds.”
Simon points out that the proper dose rate is 1 L/ha. “This is the effective dose rate and one that delivers the high level of weed control we have seen. In trials Centurion MAX gave 98% control of black-grass and 96% control of annual meadow-grass, a weed that few other ACCase graminicides can control. In over 40 trials in the EU and the UK, trials show good activity on a range of other grass-weeds; 97% control of wild-oats, 97% control of rye-grass and 92% control of brome, when applied at 1 L/ha in 200 litres of water.”
Simon reports that no significant crop effects were observed from Arysta, Interfarm or distributor trials prior to launch. “The symptom we saw last autumn was de-waxing, which then affected spring regrowth and was seen as fusing of the primary bud and flowers. But it is important to get this in perspective. Only a very small proportion of the crop area treated suffered these effects and harvest results have shown no significant difference in yield.”
“Virtually all farmers were very pleased with the level of black-grass control, confirming Centurion MAX’s superior weed control. Our new guidelines are on the cautious side, but we want to ensure excellent results and no crop issues this autumn.”
Centurion MAX contains 120g/L clethodim and is formulated as an emulsifiable concentrate with its own efficacy selected in-built adjuvant and packed in a 5L container. It is recommended for use post-emergence in winter oilseed rape and sugar beet to control black-grass, annual meadow-grass and cereal volunteers. It is applied at a dose rate of 1 litre/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 2 true leaf stage of the crop 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
