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Sugar beet growers should target a yield of at least 80t/ha to ensure the crop pulls its weight during the 2024/25 season, say experts.... Management tips for sugar beet following wet spring

Sugar beet growers should target a yield of at least 80t/ha to ensure the crop pulls its weight during the 2024/25 season, say experts.

Prospects for sugar beet this season and recommendations for herbicide programmes were discussed by agronomists and other arable advisors during a webinar hosted by crop protection experts UPL.

Using the new contract price of £40/t, sugar beet gross margins look competitive against combinable crops, says Jock Wilmott, partner and agronomist at farm business consultants Ceres Rural.

But the figures look less good when beet is considered on a cost-per-tonne basis, says Mr Wilmott, who has been advising growers about sugar beet for more than 20 years across Cambridgeshire and Hertfordshire.

“At £40/t, you would think the margins would be healthy, but if you look at it on a per-tonne basis, it isn’t as good as first thought.”

Not including the 2023/24 crop, the five-year average beet yields for the country are 71.5t/ha at 17% sugar, explains Mr Wilmott.  An average beet crop costs almost £30/t to grow. Adding £500/ha for land rate increases the average cost to £37/ha.

This means the best way to improve sugar beet margins is to push the yield.

“Looking at the prices for cereals, the issues getting wheat crops established and how well they look, beet has to pull its weight this year. It is all the more important to get the yield above 80t/ha if you can.”

Input costs

Crop inputs comprise 40-45% of overall growing costs. Harvest and transport (40-45%) represent a large proportion too, although British Sugar’s transport allowance or beet delivery service will offset some of this.

Seedbed preparation, drilling, spraying, fertiliser and agronomy costs comprise the smallest proportion but are the most important. This means total costs are more finely balanced than the £40/t headline price would suggest.

“It is all about establishing the crop well, getting it growing, and closing the canopy. This will help protect against virus yellows and mitigate any late herbicide sprays.

“Patience and attention to detail when preparing land for sugar beet will be critical this year. There is a margin in sugar beet, which has to support the other crops in the rotation, so a lot relies on a decent year.”

Most crops will need four post-emergence broad-leaved weed sprays costing at least £150/ha. Most scenarios will involve blackgrass control, adding roughly another £35/ha for Centurion Max (clethodim).

Controlling volunteer potatoes with clopyralid or adding a pre-emergence spray further increases the overall cost. And where there are issues with weed control, often it is because the spray intervals are too wide.

British Sugar technical support manager Pam Chambers says: “My view is to follow up a successful first post-emergence spray closely with a second, especially if there is a high weed burden.”

Intervals between sprays become more of an issue when it is dry. The industry has missed desmedipham to boost the activity of herbicides, but Ms Chambers believes its role can be partially replaced with adjuvants.

“In some situations, not including an adjuvant (with a herbicide) is like having gin without the tonic. In trials, I have seen a 50% increase in efficacy by including an adjuvant.”

The main reason for using an adjuvant oil with herbicides is to break down the waxes on a weed leaf surface to allow faster penetration of the herbicide into the weed, says Rob Sucking, commercial technical manager at De Sangosse.

“Ultimately, adjuvants increase herbicide uptake.  In conditions like moderate to severe frosts, high diurnal range and fast-growing crops, using an adjuvant can increase the potential for herbicidal crop phyto expected under these conditions.”

Newman Cropspray 11-E is one of the most common adjuvant oils used with beet herbicides. Growers should adjust application rates depending on the temperature, says Mr Sucking.

A dose rate of 0.75l/ha is recommended up to 18°C. This should be reduced to 0.5l/ha if the temperature is between 18-21°C, with growers advised to switch to a methylated seed oil (MSO) above 21°C.


Straight herbicides based on metamitron, ethofumesate, and phenmedipham have a synergistic effect when combined, giving 100% of control against fat hen in BRRO and UPL trials at Bracebridge Health, Lincolnshire.

“In certain situations, a co-formulated (herbicide) solution fits,” says Mr Wilmott. “A dynamic situation where you have a mixture of dry and wet periods in the spring and sprayers are busy suits straight herbicides because you can adjust the rates.”

The value of a pre-emergence sugar beet herbicide often divides opinion among agronomists and growers. But Ms Chambers says soil moisture in 2023 resulted in good weed control from a pre-em.

“If you have blackgrass, I would look to do a pre-emergence of ethofumesate plus metamitron. Another good reason for a pre-em is if you are pushed for time and think the first post-em sprays will be challenging to apply at the correct time.”

Mr Wilmott suggests growers might not need a pre-emergence spray in the absence of problem weeds – although he acknowledges that using one could certainly help to take the pressure off.

“Doing some early metamitron followed by some rain will deliver a return. However, I don’t advise you to do it until you have seen the conditions ahead.”

Herbicide-tolerant beet

Some 20,000ha of herbicide-tolerant Conviso sugar beet was grown in 2023 with British Sugar predicting a similar area this season, with the yield gap closing between Conviso varieties and conventional beet.

The one area where growers should avoid Conviso is if they have a beet cyst nematode (BCN) problem, says Ms Chambers. There are no BCN-tolerant Conviso varieties, although some are in development.

Mr Wilmott expects most Conviso beet to receive a conventional pre-emergence herbicide to help control weeds like black bindweed and give greater flexibility for the Conviso One (foramsulfuron + thiencarbazone-methyl) timing.

“One conventional broad-leaved weed spray and the Conviso herbicide is not expensive. But you also have to consider the additional cost of the seed and following the stewardship of the technology (by controlling bolters).”

There is also the question of what to do with blackgrass.

“Conviso One is a relatively good blackgrass herbicide, but it is similar sulfonylurea (SU) chemistry to that being used elsewhere in the rotation, like Atlantis (metsulfuron-methyl + iodosulfuron-methyl).”

Growers should be mindful of resistant blackgrass and use a blackgrass active pre-emergence spray and Centurion Max in a programme with Conviso One if they think they have target site resistance, says Mr Wilmott.