A great start for herbicides

Ideal conditions in autumn 2010 allowed most growers to exploit fully both chemical and cultural control measures, putting them in a much stronger position than last spring when completing their grass-weed control programme, according to Bayer CropScience.

At a Weed Screen briefing held at the company’s development farm this week, the company’s combinable herbicides campaign manager, Chris Cooksley gave a full and frank market update covering autumn applications and prospects for spring 2011 – as well as an overview of Atlantis WG resistance.

“Varying levels of black-grass resistance are present throughout the country,” Mr Cooksley acknowledges. “Essentially we estimate that growers are finding it difficult to achieve acceptable levels of control by chemical means alone in between five and ten per cent of fields.

“But cultural methods of control were more widely used and effective this year; partly due to the weather ‘playing ball’,” he acknowledged.

“During late September and early October a short spell of wet weather led to ideal soil conditions helping growers to achieve good seedbeds,” he explains.  “It also delayed drilling, allowing a flush of growth that could be subsequently sprayed off.  This has all added up to near perfect conditions for pre-em applications, giving growers good control and lower populations of black-grass.”

Mr Cooksley said pre-em herbicides have worked particularly well, especially where used in combination with cultural control measures.  “Going into spring having already achieved 80% control is not uncommon this year.  Survivors are smaller too, and with spring programmes now getting underway in good conditions, it is an encouraging start to the season.”

Despite this, Mr Cooksley said growers’ herbicide programmes still had much to be done – this was no time for complacency.  “Only about 20% of the black-grass area received Atlantis WG (iodosulfuron and mesosulfuron) in the autumn, and optimising remaining spring applications will be crucial for the overall success of this year’s weed control strategy. 

“Atlantis WG needs to go onto a dry leaf with good drying conditions, using a nozzle that gives a fine to medium spray quality.  Stable and correct boom height and a sensible speed (12kph or less) will also help to maximise control. Always apply with biopower adjuvant and ideally without any other tank mix partner.”