Harvesting tips, virus control and selecting sugar beet varieties for late harvest were under discussion at a recent BBRO open day held at Askham Bryan College, North Yorkshire.
Although early-harvested sugar beet tended to be small as a result of the dry summer, sugar beet crops have put on considerable weight since mid-October, with British Beet Research Organisation (BBRO) reporting averages of 65-70 tonnes/ha in early December.
Dr Simon Bowen, BBRO knowledge exchange and crop progression lead said while the Recommended List provided information on characteristics such as yield, suitability for early drilling and disease resistance, growers also had questions such as whether some varieties are more suitable for late harvesting.
“I think the harvesting season is getting longer. Between September and December beet can put on 30 per cent of yield depending on temperature and the last three seasons we have had a mild autumn.”
The yield increase is partly influenced by variety and can range between 20-40 per cent. Canopy growth and disease susceptibility determine how much of this later harvest yield potential is achieved.
BBRO has been looking at the characteristics which make sugar beet varieties suitable for late harvesting, said Dr Bowen. “We want an upright canopy structure to allow leaves to catch autumn light which comes at an angle. We also want a dense canopy to catch light and give frost protection.”
Dr Bowen said minimal leaf senescence is also important to maximise yield for late harvested varieties and low levels of foliar disease. Varieties on the 2019 RL showing all four characteristics are Sabatina KWS and Salamanca KWS.
Redesigning sugar beet crop protection programmes in the absence of neonicotinoid seed dressings for the 2019 season was the subject of a presentation by BBRO scientific and crop stability lead Dr Mark Stevens.
He said: “This will be the first season for 25 years without neonics. They have provided control in three areas: the soil pest complex, leaf miner and virus carrying aphids.
“Force [tefluthrin] remains so we do have a strategy to control soil pests. Yorkshire is one of the biggest areas at risk so if you have a problem, tick the box for Force when ordering seed.”
For leaf miner, Hallmark (lambda-cyhalothrin) will give some activity, said Dr Stevens, but is quite negative against beneficials. “It will become increasingly important for leaf miner and aphid control. Historically we have applied for emergency authorisation for Biscaya which gives some systemic activity but is not approved for sugar beet. If we need it in 2019 we will need to go through that route. The Dutch can use it and don’t have to go to the Government for emergency authorisation.”
In BBRO trials, new aphicide, Teppeki had ‘done a pretty good job’ said Dr Stevens but could only be applied once, giving up to 21 days’ protection. “We are looking at others which have not been approved yet – we may need to speed up authorisation or apply for emergency authorisation as the season progresses.”
BBRO is planning to increase its monitoring of aphids in 2019. Currently it has yellow pan traps at 30 sites and plans to double this to 60. “Check on the sites closest to your farm. If you only have one application of Teppeki you need to target it right,” said Dr Stevens.
Maximising beneficial insect populations was discussed. Dr Stevens said 90 per cent of aphids are now resistant to pyrethroids and that trial plots sprayed with pyrethroids this autumn, when there was quite a large migration of Myzus persicae, had twice as many aphids as untreated plots. “This is because they had taken out the beneficials. The aphids will survive and you’ll take out the predators.”
Ways of maximising beneficials could include companion cropping with crops such as phacelia and choosing sugar beet varieties with herbicide tolerance, enabling weeds to be left in longer and taken out later. “Anything you can do to encourage beneficials,” said Dr Stevens.
Variability in sugar beet crops due to this season’s weather conditions is requiring compromises when setting up harvesting equipment and a danger of over-crowning, said BBRO mechanisation specialist Stephen Aldis.
“The old school approach was a nice clean topped beet but today this could be considered over-crowned,” he said.
“We don’t want masses of green material in a clamp but also not scarring which leads to more sugar losses. Whether it’s in a week or a month err on the side of leaving more on the top – just the stem if the whole leaf is too much.”
Small beet seen this year, particularly early-harvested beet, has led to some surface losses, said Mr Aldis. “Usually contractors are good at managing losses to 0.5t/ha or below. This year that has been harder because of a lot of small roots and we have seen a bit of loss but generally we are running at less loss because there has been less damage to the beet.”
The pictured beet has the correct amount of leaf/stem material remaining, said Mr Aldis.