BBRO Advisory Bulletin No 11

Crop Growth
There are some early drilled sugar beet plants that are at the 4 to 6 true leaf and growing well on free draining and organic soils, however many crops are still very small and backward. The photographs below illustrate how slow crop growth has been in many areas this year.

Crop drilled 16.03.12

Nitrogen
Soil sampling was carried out at a number of sites and soil types across the beet growing area in February to determine available N levels at three different sampling depths prior to any ammonium nitrate being applied. Following concerns about high levels of April rainfall these sites were sampled again on the 2 May to determine available N levels following a spring application of nitrogen. None of the sites gave any cause for concern and by way of illustration the results for the site at Fotheringay (a sandy loam site) are shown in the table below.

The results from this trial site indicate that in spite of the high rainfall:

. There is sufficient N in the top 30cm of the soil profile for the beet crop
. Growth models indicate that the sugar beet roots will now be reaching at least 30 cm depth and so will be abl e to use N from lower in the soil profile

RB209 advises not to sample within 2 to 3 months of applying nitrogen fertiliser as some distortion of results can occur, so information should be treated with caution, however:

BBRO advice is:-
There is no justification for applying additional nitrogen in excess of standard recommendations.  

Where 2nd and final applications are still required these should be applied as soon as conditions allow.

Herbicides
Where pre-emergence herbicides were used this se ason they have worked extremely well.

There are a considerable number of fields where no herbicide treatments have been applied yet; these fields will generally require robust programmes with short spray intervals. Check crops with a view to spraying 5-7 days after the initial spray, where weeds are starting to 'get away'. Advice given in Advisory Bulletin No.10 is still valid and programmes such as those shown below or similar should be considered, based on a number of actives.

Other options exist and the BBRO Herbicide Charts 2012 issued earlier this year and also available on the UK Sugar Beet portal ( www .bsonline.co.uk ) should be consulted.

BBRO have 4 herbicide trials this year that are comparing herbicide programmes which include the above and also treatments based around United Phosphorous and Makhteshim Agan products, we will be discussing these at the forthcoming BBRO Open Days.

Volunteer potatoes
Volunteer potatoes continue to emerge albeit slowly. Clopyralid applied in tank mixture with ethofumesate containing products, is the best treatment against volunteer potatoes in sugar beet. The effect on progeny tubers is carried through to succeeding generations, thus reducing the threat from volunteers in the second year after treatment. Note that the new double strength formulation of clopyralid, Dow Shield 400, has been launched, this new form ulation contains twice as much clopyralid and is applied at half as much per hectare as that used with Dow Shield 200. The first application of clopyralid should be made when the volunteer potato shoots are between 5cm and 10cm tall.

Blackgrass
Where black-grass is present/expected monitor growth and aim to apply sprays targeted at this weed at the 1 to 2 leaf stage of the grass weed. Aim to use ethofumesate in the programme but ensure that the 1000 g of ai/ha in a three year period is not exceeded.

Re-drilling
We are now at the point where it is unlikely that re-drilling will be a viable option, if you are contemplating this then you are strongly advised to consult with your local British Sugar Ar ea Manager before taking any action, or phoning the Advisory Helpline. (See notes in Advisory Bulletin No.10)

Crop grazing
Grazing by birds and mammals is a persistent problem in some areas and crops are slow to recover due to the cold and wet conditions. Pigeons are generally congregating in small groups of 20 or so and can be seen grazing on beet which are at the first and second pair of true leaves stage. Continue with deterrent activities as appropriate.

Slugs activity should be monitored and slug pellets applied if damage is occurring in particular check heavier soil types.

Sprayer hygiene
Sprayer hygiene was mentioned in Advisory Bulletin 9, this is even more important now as the back log of spraying has increased considerably for many. Ensure that good sprayer hygiene is practiced when switching between crops. Each year there are a examples of SU damage to sugar beet where sprayers have not been rinsed thoroughly after spraying cereal crops with SU products.

BASIS points
Two BASIS points in total (not per bulletin) have been allocated for the period between 01/06/11 and 31/05/12 reference CPD/20108/1112/a. In order to claim these points please contact Jill at BASIS registration on Jill@basis-reg.co.uk  

For technical queries contact the BBRO helplines:
Pam Chambers , pam.chambers@rothamsted.ac.uk 07887 628357
Colin Walters colin.walters@britishsugar.com 01733 422088
Caution : this information is based on results of experiments and experience but cannot constitute a recommendation.