Competitive herbicides warrant consideration

30 October 1998

Competitive herbicides warrant consideration

COMPETITIVE pricing means new herbicides are well worth considering this autumn, particularly if they remove the need for a spring follow-up for broad-leaved weed control.

So says Cereals 99 host Tim Whitehead who manages 800ha (1980 acre) Vine Farm near Royston, Herts, for Velcourt.

All 420ha (1040 acres) of cereal drilling was completed on Tuesday 20 October, despite the acquisition of an extra 200ha (490 acres) of land on Sept 16 and severe hold-ups following 78mm (3in) of rain in four days at the end of the month.

Now herbicide spraying is the priority and Mr Whitehead is keen to try alternatives to the farms traditional isoproturon/diflufenican mix.

Lexus Millennium (flupyrsulfuron-methyl + thifensulfuron) has most appeal. Even at full rate it costs virtually the same as the farms standard 2.5l/ha ipu plus 2.5l/ha Javelin Gold (ipu + diflufenican).

Ideal application timing is the same two-leaved stage of blackgrass as for ipu, but persistence is believed to be greater, notes Mr Whitehead.

A wider spectrum of weed control, including cleavers, should mean a spring broad-leaved weed clean-up is unnecessary, saving up to £20/ha (£8/acre).

Problem weeds selected for by repeated ipu/dff spraying should go too. Cranesbill is a prime example, requiring a spring dose of Ally (metsulfuron-methyl) on one farm field walked by Mr Whitehead.

Although the Lexus product lacks wild oat control, spring germinators meant 80% of the cereals were over-sprayed this year, even after ipu, he notes. The plan after Lexus Millennium is to return with reduced rate Topik (clodinafop-propargyl) or Cheetah (fenoxaprop-ethyl) in March or April, according to need.

Some autumn Hawk (clodinafop-propargyl + trifluralin) will also be tried, although Mr Whitehead considers it expensive. "Novartis now says lower rates will do the job at a price which is competitive with ipu. But I think that might be cutting it a little fine. We will try some to see."

However, most of the cereals will still receive ipu/Javelin Gold. "Its what we know and we know it works.

"All we need now is a couple of dry weeks. Im very reluctant to put ipu on if there is a risk of an inch of rain within 48 hours."

&#8226 Results of a more extreme approach to cutting spray passes will be demonstrated by Velcourt at Cereals 99. "In our System 2000 trial were using new agrochemical technology to reduce spray passes and cut operational costs to the bone. With each sprayer pass costing £7/ha it could be well worthwhile," explains technical director Keith Norman. &#42


&#8226 Drilling completed 20 Oct.

&#8226 Herbicide spraying priority.

&#8226 IPU/Javelin Gold standard.

&#8226 Lexus Millennium promising.

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