Get beet off to a strong start – Farmers Guide

Rapid establishment of sugar beet drives yield and gets crops past the most vulnerable stages for virus infection quicker, but how do we achieve that and what are the pitfalls to avoid?

Aim to hit weeds when small (cotyledon stage), before they compete with the crop and slow its establishment. Any weed can be problematic, but the most damaging tend to be taller species that grow above the crop, such as fat hen, redshank, and volunteer potatoes.

Targeting weeds at the cotyledon stage also avoids the need for products or mixes that may be “hotter” on the crop. There is a good range of contact and residual chemistry available, so discuss the best options with your agronomist.

Good spray coverage is essential for optimum herbicide efficacy, and recent research shows flat fan nozzles remain the most effective for hitting small weeds in sugar beet, not bubble jet nozzles. When targeting grassweeds with contact herbicides, make sure weeds are actively growing to take up the chemistry – this may not be the case if weeds have been knocked back by an earlier herbicide application.

Remember, only one application of foramsulfuron + thiencarbazone-methyl is allowed, which should be applied at the correct timing (2-4 true leaves of fat hen). Ensure you follow stewardship guidelines on the product label.

Conviso and non-Conviso fields must also be clearly marked, and sprayer operators made fully aware of where they are to avoid any costly mistakes.

There may be ALS-resistant weeds in some fields, so use a conventional treatment early where this is a problem, otherwise once you realise weeds such as poppy and chickweed are not dying, they may be too big to control.

Crops need balanced nutrition to establish quickly and build healthy canopies, with early nitrogen being particularly important. Sufficient nitrogen must be available as beet starts growing rapidly from the 4-6 leaf stage.

Assuming around half of total nitrogen has been applied to the seedbed, the remainder should go on by the two-leaf stage, so do not leave it too late.

Urea-based products take longer to become available to crops than ammonium nitrate based fertiliser, so consider this when timing applications. It is especially true for urea products that include an inhibitor; something that is mandatory for all urea applied after 31st May.

Don’t forget micronutrients too. These can sometimes be applied with post-em herbicides, but only if products are fully compatible, so check labels carefully.

Getting crops established and past the 12-leaf stage as quickly. as possible is key to mitigating risks from aphids and associated virus. Beyond 12 leaves, sugar beet becomes more resistant to virus transmission.

Fortunately, Rothamsted Research’s aphid forecast, published in early March, suggests that after January’s cold spell, most aphids will not arrive in crops until May this year. That is comparatively later than normal – in bad virus years, such as 2020, aphids arrived in March just as crops were emerging.

Settled weather this March has allowed many crops to be sown in good time into decent conditions, so hopefully these will be well advanced once aphids appear.

Avoid anything that restricts development though, be that sub-optimal nutrition, or weed competition, and monitor crops closely for aphid activity.

If/when treatment is required, there are now three options available for this season. There are differences between products, especially in their effects on other pests and mode of activity, so again, speak to your agronomist about the most appropriate option.