Top weeds in rape can all be cost-effectively controlled

A recent survey of UK oilseed rape growers has identified Black-grass, Crane's-bill, Cleavers and Charlock amongst the most difficult weeds to control and BASF are confident that they have a suitable and effective herbicide in their range to tackle all the major weeds in this valuable crop.

"Winter oilseed rape has become one of the top performers when it comes to gross margins, but in order to benefit from the buoyant market demand for oil and hence good pricing, growers will have to look to improve their rape yields further. This has to start with a well-established crop, free from weeds. It is important to take out weed competition early in rape crops, as autumns are getting milder and weeds are growing more rapidly. But have weed problems changed since the crop has been so widely grown and have we the right herbicide tools to deal with them?" asks Paul Rawson, Oilseed Rape Product Manager for BASF.

He explains that BASF commissioned a survey of over three hundred rape growers across the UK and asked them which weeds they found the most difficult to control. The survey confirmed that the leading weed species was Black-grass, with 25% of growers citing this weed as being the most difficult to control and the one for which they were least satisfied with the current levels of control achieved. The next most difficult weeds to be cited were Cleavers, Crane's-bill (Geranium species), Charlock and Thistles, with around 12-13% of growers selecting these weeds individually. These top five were followed by Poppy, cited by 17% of oilseed rape growers.

"In many respects there were only one or two surprises from the survey, as the top weeds have been a problem for a number of years. Black-grass control certainly doesn't get any easier in any crop and the market is always looking for active ingredients that have some useful effects on this weed. Some weeds such as Crane's-bill have come to the fore mainly because they have been a gap in the weed spectrum of some herbicides in cereals as well as rape. Others such as Poppy may well become more widespread as actives such as trifluralin disappear. Others such as Cleavers, Chickweed and Mayweeds have been a problem across the arable rotation for years," explains Clare Tucker, Agronomy Manager for BASF.

The good news for growers is that BASF have a broad range of herbicides that can tackle virtually all these weeds in oilseed rape. Their range includes the basic building block Butisan S (metazachlor) which gives excellent control of Speedwells, Chickweed, Dead-nettle, Groundsel, Mayweed, Shepherd's-purse, Sow-thistle, Annual Meadow-grass and Black-grass.

"Other active ingredients have been co-formulated with tried and tested metazachlor in order to broaden the weed spectrum and to add in specific weed species. For example Novall and Oryx contain metazachlor and quinmerac, with the quinmerac adding in extra activity and persistence on Common Poppy and Cleavers as well as Speedwell, Fool's Parsley and Red Dead-nettle."

"Then there is the new active ingredient dimethenamid-p which is in Springbok (metazachlor and dimethenamid-p) and, new for this year, Shadow which contains all three key actives dimethenamid-p, quinmerac and metazachlor. Dimethenamid-p has a similar weed range to metazachlor, but has particular strengths on Crane's-bill, Shepherd's-purse, Black-grass and Annual Meadow-grass. It is also superior on Poppy and Cleavers. As with metazachlor, it's a low-risk resistance active for use on Black-grass. It will be a particularly useful active to integrate into a Black-grass control programme from now on."

Clare explains that Shadow solves all the common weed problems on farms where both Cleavers and Crane's-bill are a problem. "In development trials Shadow gave Cleaver control of over 95% with very good consistency. It is also the best, most consistent Poppy option following the loss of trifluralin."

BASF also have one of the most widely used graminicides in Aramo (tepraloxydim). Being a "dim" herbicide, it remains the best choice against Black-grass where both target site and enhanced metabolism resistance is suspected. It will also control other grasses such as Wild-oats, Sterile Brome and Perennial Rye-grass.

Paul Rawson comments that weed control has not become any easier, with a range of weeds identified as being difficult to control. "There are certainly some challenges that we need to overcome. But we do have a good selection of active ingredients in oilseed rape and in the last year the new active ingredient dimethenamid-p has added to our armoury. BASF have continued to invest in the rape crop and can offer UK growers an excellent range of oilseed rape herbicides from which to choose."

For further comment and information please contact Clare Tucker, BASF on 07768 687707 (mobile) or by email at clare.tucker@basf.com