Issued: 2nd March 2021

Virus Yellows Forecast 2021 and Vydate 10G update.
Cruiser SB will not be applied on seed in 2021
•With February temperatures fluctuating from very cold to unseasonably warm conditions,especially during the last three weeks of the month, this has meant the independent virus
yellows forecast has been uncertain with regards to the 9% trigger threshold for the use ofCruiser SB on seed.

•The 1st of March forecast predicts that 8.37 % of the national sugar beet area will
be affected by virus yellows by the end of August 2021. The graph below shows the2021 forecast in a historical context, reinforcing the low virus forecast for this season.

PM = Pest Management

In 2020 thevirus forecast
was >80%

For 2021 thevirus forecast
is <9%

Data kindly provided by Rothamsted Research.

•

Under the terms of the emergency authorisation from HSE and DEFRA this means that theuse of Cruiser SB has not been triggered and will not be applied to seed this season.

•The forecast also predicts that the date of first aphids arriving in crops will be from the18thMay. This is much later than when aphids were first recorded in crops in 2020 which
was in late March.

•Clearly, the cold weather has had a significant impact on overwintering aphid populations,both reducing their numbers as well as the date of their migration into the 2021 crop. Thisis a very similar national forecast to that in 2018. Aphids were first recorded in crops in late
May 2018. This is very welcome news for crops in 2021.

•

Once seed is on farm, drilling into good seed beds, as soon as possible, will ensure crops
establish quickly. Consequently, plants will be more mature, resilient, and resistant to theimpact of virus when aphids finally arrive. Crops will still need to be monitored closely foraphids and for the appropriate thresholds to trigger any necessary foliar insecticides.

•BBRO will, as is usual, be monitoring crops and will have a network of yellow water pan
traps to assess aphid numbers during 2021. This information will be available via theBBROplus website and reported regularly in the BBRO Advisory Bulletin.

•Some further news. An Emergency Authorisation for the use of Vydate 10G has been
approved by the HSE (EA number 0536 of 2021) This is for the control of free-living
nematodes (Trichodorus, Paratrichodorus spp and Longidorus spp) in sugar beet. The rateof use is 30g/100 m, for application at drilling up to the 30st April 2021.

•Use up end date: 30th April 2021.

•Disposal and storage end date: 31st May 2021.

•It is important that both the label and nematicide stewardship scheme conditions for use insugar beet are fully adhered to. The Vydate 10g Stewardship scheme (A guide to bestpractice 2020/21) can be downloaded from the Corteva website.

After such a long, wet winter, land is eventually beginning to dry out, and the possibility ofdrilling is now a reality on light land. However, check land is sufficiently dry at cultivation
depth to reduce risk of smearing and compaction. Check soil temperatures as they are still
low and subject to large fluctuations. Ideally, temperatures need to be consistently
increasing before drilling early.
Make sure you mark-up different varieties and seed stocks carefully in each field to help
you make subsequent decisions about foliar sprays of herbicides, insecticides, andfungicides. Avoid drilling before mid-March those varieties marked with a red cross on theRL list to reduce bolting risk. Remember also to manage Conviso Smart seed carefully anddrill Conviso Smart varieties after mid-March to reduce bolting risk.
There is existing approval for one foliar spray (Teppeki) and Emergency Authorisation
applications for two more foliar products have been submitted. These applications are
currently being processed and we will advise you on these as soon as we can. This should
be well ahead of any application dates. The supply of these products has been planned.
It is important to remember that whilst the number of aphid vectors will be lower thisseason, there are still likely to be a considerable number of sources of virus on farm
following the high levels in 2020. It remains critical therefore to ensure potential sourcesof virus are removed, especially before temperatures start to rise as we go into late springand early summer. Groundkeepers, leaf growth on beet spoil and fodder beet heaps andparticularly any energy/AD beet or unharvested sugar beet still in the ground will all bepotentially key sources of virus (and foliar diseases such as cercospora too). As soon as thecurrent difficult soil conditions allow, remove, or manage these virus-infected sources.

Book now for BeetTech21, our virtual winter conference for updates on Virus Yellows, weedcontrol, seed bed preparation and drilling in current soil conditions and cercospora control. The
event will commence with the release of 4 short videos on Monday 8th March and culminate in alive discussion on Thursday 11th March – please book to ensure you don’t miss out.
https://bbro.co.uk/events/

British Beet Research Organisation, Innovation Centre, Norwich Research Park, Colney
Lane, Norwich, NR4 7GJProf Mark Stevens mark.stevens@bbro.co.uk 07712 822194
Dr Simon Bowen simon.bowen@bbro.co.uk 07718 422717
Stephen Aldis stephen.aldis@bbro.co.uk 07867 141705
General Enquiries info@bbro.co.uk

Two BASIS points in total (not per bulletin) have been allocated for the period between 01/06/20 and
31/05/21 reference CP/100686/2021/g. To claim these points please email michele@basis-reg.co.uk
Two NRoSO points in total (not per bulletin) have been allocated between 01/06/2020 and 31/05/2021
reference NO468433f. To claim these points please email NRoSOCPD@cityandguilds.com