BBRO Advisory Bulletin No 7

Rainfall has been very variable across the sugar beet growing regions with amounts ranging from less than 11mm to over 50mm it has however been very welcome especially for the later drilled fields.

Final nitrogen applications and early post emergence herbicides are priorities for sugar beet crops during the next week. It is advisable to leave 2 to 3 days between fertiliser and herbicide applications to minimise the risk of scorch and possible plant loss, especially if we continue to alternate between warm and cold weather conditions.

Crop Growth Stage

Growth stages of sugar beet plants range from not yet emerged to first true leaves just showing, the recent rainfall should mean good emergence now from late drilled crops.

Plant Populations

Aim for 90,000 established plants/ha across all field areas taking into account the estimated plant establishment (as the mid-point between 80,000 and 100,000). Plant populations can be assessed by carrying out ten or more 20m counts on several different rows in different areas of a field to obtain an average figure. Using a 20m length of string anchored to a stick or cane will be more accurate than trying to pace out 20m.

Plant population counts should be carried out over the next few weeks to ensure adequate plant numbers have been achieved. Where crops have poor and uneven establishment with less than 50,000 plants/ha it may be worthwhile re drilling. Much will depend on how evenly distributed the beet plants are, how good establishment is likely to be from the re sown crop and the cost of re drilling. Before re drilling, check as to whether it is necessary to drill the whole field or just a part of it.

Where less than optimum populations have been achieved you may wish to contact your British Sugar area manager or agronomist to discuss strategies for next year to improve populations.

Nitrogen

All but the very latest planted crops should now have received their second and final nitrogen application.

Herbicides

The recent rainfall will have activated pre-emergence herbicides where they have been applied and will help 'buy' some time where post-em herbicides are delayed.

There has been concern over recent days regarding herbicide applications and the sometimes severe air frosts. If possible the best advice is to delay herbicide applications when frosts are forecast and then use more robust treatments when conditions are more favorable. Rainfall has also meant that some of the heavier fields are more difficult or impossible to spray due to travel conditions being too 'sticky'.

In most cases weeds are still very small and are at the cotyledon stage with growth appearing to be relatively slow. There are a few fields though where first true leaves are starting to show on some weed species e.g. knot-grass and black-bindweed, these fields should be a priority for herbicide treatment.

Volunteer OSR is apparent in quite large flushes on some of the more organic soils but mainly still at the cotyledon stage, these are easily controlled with triflusulfuron-methyl (as in Debut). This active is also useful against annual mercury, which seems to be an increasing problem in some areas.

Black-grass is emerging, with a few plants at the two leaf stage, ethofumesate (as in Ethofol 500 and Ethosat 500) has activity against black-grass and is useful where r esistance to the 'fops' and 'dims' has been identified. Aim to use ethofumesate as early as possible in the program but take care with rates whilst beet are still small and do not exceed the maximum permitted 1000 g ai/ha of ethofumesate over a three year period on the same field.

Pests

Rabbit fencing is being used to good effect on an increased number of sugar beet fields this year, ideally fences should be erected prior to crop emergence. Ensure that batteries are checked and recharged at least weekly it is also important to have a good earth. In Norfolk growers are apparently noting that rabbits are now taking a run at fences and jumping them!!

Mouse damage continues to be reported but generally on fields where drilling depth has not been adequate either due to incorrect setting of drill coulters or 'cobbly' seed beds.

Monitori ng for slug damage should be a priority over the next few days as the moist seed beds will encourage activity.

An isolated case of re-drilling due to wireworm damage has been reported.

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.
If you experience problems receiving this bulletin, contact the helpline on 0870 2402314

Feedback

Click here to have your say. Comments may be used in NFU publications.

No comments have been made.

Add Your Comments

Close window

Name:
Email:
Comments:
Verify Code:
Submit