Beet crops at risk if bolters not rogued

News Release
26 September 2014

Beet crops at risk if bolters not rogued

Farmers need to change their summer management to keep fodder beet sustainable as an increasingly popular supplementary feed in New Zealand, the seed industry has warned.

According to the New Zealand Grain and Seed Trade Association, crops should always be checked for bolters and there are benefits to farmer’s rogueing bolters.

“A single bolter can produce approximately 1,500 wild seeds, which then drop to the soil and germinate in subsequent seasons as the soil is disturbed,” explains NZGSTA general manager Thomas Chin. “These areas could potentially be thick with weed beet in future years, if not managed.

“These are lessons learned in Europe many years ago. Farmers there reduced the potential to continue fodder or sugar beet production in paddocks they had previously used to grow the crop because of the seed burden created by bolters.”

Fortunately for NZ, we have a significant pastoral base and use many crops in rotations, which do provide the opportunity to manage a weed beet burden, in subsequent seasons. However it is better if the control occurs at the bolter stage.

There is also the risk of cross pollination affecting specialist vegetable seed crops of beet and chard growing on the Canterbury plains. Any outcrossing would ultimately lead to affected vegetable crops being rejected or downgraded for contamination, Chin says.

The level of bolters that occurs has been satisfactory, however in areas where farmers have seed production neighbours, it is important that farmers are talking to each other about the location of crops for seed and forage production.

Beets are wind pollinated and Fodder beets can outcross with Redbeets and Swiss Chards up to 10 kilometres away.

The mechanisms which are not yet fully understood by the scientific community and the presence of bolters are accepted as an inevitable part of growing beet crops.

What is known is that that the incidence can be accentuated by cold weather during early growth, or by stress factors such as poor fertility, drought, or herbicide stress during the growing season.

One of the first things growers can do is to make sure crops are not sown too early.

In all beet crops, removal of bolting beet plants is an accepted practice farmers undertake as a normal part of the farming operation. This would need to be done before the plants flower. This should involve breaking the stem at ground and leave on crop canopy. If a crop has started to set seed, remove the bolter plants from the paddock.
ENDS

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