FAR reaching success
FAR reaching success
A ROUTINE herbicide regime has again proved its potential to maximise sugar beet margins in BBRO-funded work at Morley Research Centre.
For the second year running, FAR programmes using repeat phenmedipham, ethofumesate (activator) plus residual mixes gave the greatest margin over herbicide costs, including a £6/ha/pass (£2.40/acre/pass) application charge.
"The best of the FAR programmes are beating the best of the conventional programmes," says MRCs Martin Lainsbury. "But adding oil is essential to get the most from FAR.
"From the second spray onwards always include it, but dont put oil in the first spray because the beet could be very sensitive. The oil increases herbicide activity but decreases crop safety."
The key is hitting the first flush of weeds when they are only as big as a pin-head poking through the seed-bed. "The timing of this first application is critical. It should be followed at seven-day intervals for at least the next couple of passes where there is further weed emergence."
That may make the method unsuitable for growers with beet distant from the farm or other crops competing for sprayer capacity, says Mr Lainsbury.
In the first years results it was hard to see how Debut (triflusulfuron-methyl) fitted into the FAR system.
But using Venzar (lenacil) instead of Goltix (metamitron) as the residual element in 2001 and adding 10g/ha of Debut proved a top performing programme on the heavy soil site at Otley, Suffolk.
"Chickweed, cleavers, volunteer oilseed rape and charlock were the main weeds and Debut mixes were more suited to this weed spectrum. But you must mix with Venzar rather than Goltix," says Mr Lainsbury.
Another pointer from the 2001 work is that new product Betanal Expert (phenmedipham, desmedipham + ethofumesate) will need rates kept up.
"Aventis informs me that if you drop below 0.75 litre/ha there is not enough of the oily-flowable formulation in the tank to make the mix work," says Mr Lainsbury.
That is reflected in results showing only 50% weed control when 0.5 litres/ha of Betanal Expert was used in the FAR programme, compared to 75% control with 0.8 litres/ha.
However, even at the 0.8 litre/ha rate, the products place in FAR programmes seems doubtful. "The Betanal Expert + Goltix and high rate Volcan Combi FAR programmes generated some of the lowest margins," says Mr Lainsbury.
Despite the trials edge of FAR plus oil programmes, a pre-emergence such as chloridazon may still have a place. "FAR does offer the opportunity to maximise margin, but a pre-em before the FAR programme buys you a little leeway in case you cant get the first post-em spray on." *
Beet quartet
Betanal Expert is one or four new formulations of sugar beet herbicides expected to be available this spring. Expert has the same phenmedipham, desmedipham and ethofumesate actives in almost identical amounts to Betanal Progress, which it replaces, but is formulated with castor oil. Another new Betanal brand containing phenmedipham and desmedipham is expected and an ethofumesate plus metamitron mix called Galahad will be launched. Golmet, a metamitron plus chlorpropham mix, completes the quartet.
• FAR = Phenmedipham + Activator + Residual.
• Add oil from second spray.
• For cleavers switch Venzar for Goltix and add 10g Debut
• Consider using a pre-em.
The FAR strategy works well,but may not suit everyone, says Martin Lainsbury.