5 September 1997

Combination speeds uptake

GRASS weed and volunteer cereal control in oilseed rape is set for a boost this autumn thanks to a new herbicide/adjuvant combination.

That is the claim from Zeneca for a mix of its Fusilade (fluazifop-P-butyl) herbicide and newly registered adjuvant Partna.

By supplying the right mix of surfactants and oils Partna ensures greater spray retention and more even droplet spread on the leaf surface, says Zenecas herbicide technical service manager, Trevor Culley.

That speeds herbicide uptake, so more reaches the weeds growing point more quickly.

In 28 trials from 1992-96 Fusilade and Partna gave 99% control of blackgrass compared with 95% using the same rate of Fusilade with Agral. Ryegrass control rose from 70% to 85%.

Improved activity means there is scope to cut the rate of Fusilade under optimum conditions, notes Zeneca. Fusilade plus Agral has a label rate of 0.5 litres/ha in autumn rape, but growers often cut that to 0.25 litres/ha. A mix of the same rate of Fusilade plus Partna will give better results, so the Fusilade rate could be cut still further in the right conditions, says Zeneca.

Alternatively, the mix could be used to control larger, well tillered weeds later in the season.

Cost is £6/litre, with 1 litre needed for each 200 litres of water applied.n