28 August 1998

How our eight barometer farms

are planning strategies

With blackgrass rarely a

problem on our eight

barometer farms around the

UK, autumn weed control

offers plenty of scope for

cost cutting.

Andrew Blake reports

DIFFERENT weed challenges, variable control last year and cost concerns look set to bring changes in herbicide use on farmers weeklys eight regional representative farms this autumn.

In West Sussex, Patrick Godwin will have to concentrate much more on cleaning up annual meadow grass in his cereals. "We have got some quite dirty fields and it is a real yield sapper in wheat."

He blames reduced isoproturon (IPU) content in his IPU/Stomp (pendimethalin) mixtures. "We have cut to 1-1.5 litres/ha of IPU, but we may have to up that a bit because the meadow grass has been slipping through the net."

Main caution next season involves adjuvants through his Lo-drift nozzles. He believes the combination may have caused a slip in ryegrass and wild oat control in wheat from Grasp (tralkoxydim).

South Devon-based Stewart Hayllor will use yet more pre-emergence Treflan (trifluralin) on his cereals after good results on meadow grass and ryegrass, especially in winter barley. "We did about 80% of the cereals last year, topping up with HBNs and IPU. We shall probably try to get round everything this time."

He believes Butisan (metazachlor) is too expensive to consider for oilseed rape. Laser (cycloxydim) will probably be applied against grass weeds, with broad-leaved weed control still undecided.

In Norfolk David Pettits planning is still in the air. "It depends very much on chemical prices," he says. "We shall probably go the IPU route on the cereals with rates depending on the type of ground, but I have no definite ideas yet. As far as I know we do not have resistant blackgrass.

"The oilseed rape programme will be based on 2 litres/ha of trifluralin post-drilling and the beans will get post-em simazine. We need to keep things simple and cheap, but we have few corners left to cut."

Volunteer cereals in his rape are rarely troublesome now that pre-crop ploughing is used to bury chicken manure applied to the preceding cereal stubble, he notes.

Despite poorer than usual cleavers control in cereals this year, Steven Mackintosh is unlikely to depart from his basic 1.5 litres/ha IPU + 0.5 litres/ha diflufenican approach. Grass weeds on the Herefordshire farm he manages are no problem compared with broad-leaved ones, he says.

"Our autumn weed control is fairly standard. We probably wont change even though I was disappointed with some of the cleavers control, which I put down to exceptionally mild, wet conditions."

Buying as cheaply as possible will get the most attention, he says. "Early shopping around gave us few definite answers."

In Staffs Steven McKendrick also foresees little movement from his low rate IPU/DFF cereals strategy. "We do not have blackgrass," he notes. "The main thing is that we shall be trying to buy more competitively. We have got to screw the job down somewhere."

Pendimethalin is preferred to IPU in places, he notes. "We reckon it works better on peaty land. Some of our rented ground has bad wild oats and cleavers, and we have used low rate Stomp. But we still always have to come back in the spring."

For York-based Keith Snowball poppies are an increasing problem which may mean a further move away from IPU/DFF mixtures and into pendimethalin for the cereals. "The poppies are getting away from the DFF, and trying to take them out later with MCPA is not working. Sulfonylureas can check crop growth in a cold spring, especially if mixed with CMPP or oxytril for speedwells," he says.

"We are seeing if we can do it all in the autumn with 1 litre/ha of Stomp plus 2 litres/ha of IPU." Although the farm has no blackgrass, some IPU is still needed to deal with rough-stalked meadow grass, he says.

"The Stomp should have some effect on wild and volunteer cultivated oats, though not as much as our previous 4 litres of IPU." Using Topik (clodinafop-propargyl) to remove volunteer oats is too expensive, he says.

"For oilseed rape I am a big believer in Kerb because it takes most weeds in most situations. But where we have poppies or cleavers we have to use Butisan, though it is expensive. I just wish chemical suppliers would offer more trust deals. We have had some fertiliser on that basis this year."

In Scotland, where Eric Haggarts grass weed problems are confined to headland annual meadow grass and the main cereals target is broad-leaved weeds, he intends to stick with a mixture tried for the first time last year, namely Tolkan/Bolero (isoproturon/diflufenican + terbuthylazine) at 1.25 and 0.25 litres/ha, respectively. "We had some good results with it. Crops were very clean in the spring."

Butisan at 1.2 litres/ha should be enough to allow his vigorous hybrid rapes Synergy and Pronto keep ahead of weeds, he says.

"But the real need is to get prices down." Continental growers pay much less, he notes. "I am putting a lot of pressure on our rep, although he says products cannot be sourced from makers any cheaper."

Northern Irelands Michael Kane is happy with a standard IPU/Treflan mix both pre- and post-emergence on winter wheat and barley. "We used some Lexus Class (flupyrsulfuron-methyl + carfentrazone-ethyl) last time but the broad-leaved control wasnt as good as I expected. It left a bit of corn marigold which IPU normally controls quite well. But we probably should have used it much earlier. We sprayed quite late to control silky bent grass."

Main change this autumn will be that most treatments will be post-emergence to permit tank-mixing of vital anti-BYDV insecticide, he says. "We have usually been two-thirds pre-emergence."

BAROMETER SHIFTS

&#8226 S: Annual meadow grass focus.

&#8226 SW: More pre-em trifluralin.

&#8226 E: Cheap & simple targets.

&#8226 W & Mids: Little change.

&#8226 N: Move to pendimethalin.

&#8226 Scot: Prices main concern.

&#8226 NI: BYDV influence on timings.