Arable News

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Anticipating volunteer bean problems in wheat

The newly introduced Three Crop Rule has resulted in a much expanded area of pulses being grown in the UK. In particular where winter or spring beans have preceded winter wheat, growers are being warned to look out for volunteer beans in their cereal crops, according to Christine Lilly,Technical Manager for Frontier Agriculture.

In previous years Christine has seen large clumps of between20 and 30 bean plants growing together across fields of winter wheat.  Volunteer beans are likely to be much more widespread this autumn and growers should be monitoring them and taking action to get rid of them. They need to be removed as soon as possible, as they shade the wheat crop and compete directly with it. More importantly they also shade out black-grass as it emerges and wont allow contact post-emergence black-grass herbicides to work adequately, says Christine.

She points out that there used to be an easy, straight forward solution to this problem.  We had the herbicide Pixie (which contained DFF and mecoprop-p), which was widely used. ButPixie is no longer registered and growers are seeking alternatives. At FrontierAgriculture we decided to re-examine this potential problem and to identify the best products for controlling volunteer beans. In three trials in three different locations Spitfire (florasulam and fluroxypyr) together with a methylated rape seed oil adjuvant, as is recommended on its label, did a good job at controlling volunteer beans, as did Cyclops (bromoxynil and DFF). These products were applied on the 7th November when the volunteer beans were at the 4leaf stage. The mean level of control from Spitfire + Tonto was 98.1% and from Cyclopswas 99.1%. But Cyclops was a lot faster acting. Assessed just 6 weeks after application, Cyclops had already achieved 99% control, whereas the alternative had just managed 50% control. Competition from volunteer beans was removed morequickly.

Also Spitfire contains an ALS inhibitor, whereas Cyclopsisnt and having a non-ALS alternative would give much more flexibility when deciding about the full weed control programme in the wheat crop, she says.

Christine warns growers that when they use Cyclops to take care that the maximum level of DFF applied per hectare which is 120 gmsa.i./ha across the total season is not exceeded.  Cyclops at 1 l/ha applies 27 gms a.i./ha ofDFF and at 1.25 l/ha it delivers 33 gms a.i./ha.  Where pre and peri emergence sequences of DFF-containing products such as Liberator or Vigon are used for grass-weed control, growers could already be applying 90 gms a.i/ha.

Cyclops is a worthy successor to Pixie, controlling volunteer beans and rape as well as many other difficult broad-leaved weeds such as groundsel, speedwell, field pansy and chickweed, says Nufarms Marketing Manager for UK and Ireland, Jon Staton.

It was launched late last year but has already found its place as a non-ALS cereal herbicide that delivers rapid post-emergence volunteer and weed control. You cant afford not to control volunteer beans in cereals,as if you don’t, harvest will be slower and cleaning and drying costs much higher. Nor can you afford poor black-grass control if this pernicious grass-weed is shaded by volunteers.

Cyclops works well in cooler conditions, making it ideal to use this autumn when we are anticipating a rush of both bean and rape volunteers in cereal crops, concludes Jon Staton.


  • Written by: Farmers Guide
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