After the first year of BBRO’s herbicide “systems” trials, manufacturer’s pre-formulated products have shown a slight advantage in sugar beet weed control programmes.

Speaking at the BBRO winter conference, independent agronomist Pat Turnbull told delegates that the pre-formulated products performed better at certain sites when timings were stretched.

However, she urged caution when reading too much into a single season of data. “The wet conditions and soft weeds certainly helped the efficacy of certain programmes, but in another season this may not have been the case,” explained Dr Turnbull.

Active ingredients
Betanal maxxPro Desmedipham + ethofumesate + lenacil + phenmedipham
Betasana Trio Desmedipham + ethofumesate + phenmedipham
Debut Triflusulfuron-methyl
Twin Ethofumesate + phenmedipham

Despite urging caution and associated higher costs of the preformulated products such as Bayer’s Betanal maxxPro, Makhteshim’s Twin and United Phosphorus’ Betasana Trio, the flexibility and reduction in time taken to fill the sprayer were clear advantages.

“They offer less down time, which is an important factor in a heavy spring workload. Also, where applications were delayed, programmes based around these products provided better weed control, so would be flexible in a catchy season,” says Dr Turnbull.

Some applications where the T2 spray was delayed did show some negative effects on crop vigour; but applications took place on bright, hot days which Dr Turnbull said would normally be avoided in a commercial field situation.

“The ‘system’ trials were designed to be extremely rigid, with strict product programmes and timings, so the overall control could have been improved.

“In a field situation, extra management and tweaks from an agronomist could have been implemented,” she said.

The trials also showed that tank-mixing your own programme using many single actives could reduce adjusted yield due to poorer weed control when sprays are delayed.

Soils rich in organic matter can pose a problem for weed control, but an agronomist-devised programme containing Betanal maxxPro and a high rate of Debut was included on one fen trial site.

“It didn’t provide the best control in terms of total weed kill, but it kept the weed biomass at a low level below the canopy and gave an added adjusted yield benefit at harvest,” said Dr Turnbull.

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