3 April 1998

Keeping wheat crops up

and running

Novel fungicides look set to

receive a good airing on our

barometer farms. But

management of other early

season inputs remains

under scrutiny.

Andrew Blake reports

AFTER making runaway early season growth, wheats at The Homme near Ross-on-Wye currently look a bit more normal. But a close watch is being kept on both crops and costs.

"It is a topsy-turvy spring," says arable manager Steven Mackintosh. "I usually have two basic growing programmes at the back of my mind. This year I have probably got five." Fields merit individual assessment more than ever, he suggests.

"I have never been so conscious of the need to avoid over-spending. But holding back on growth regulators and fungicides would be false economy."

Chlormequat to counter flat crops has been the most pressing need. "The cost of lodging can be horrendous. It can throw all the benefits you might get from new chemistry out of the window."

Compared with other options chlormequat, split three ways if necessary, is cheap and effective, maintains Mr Mackintosh. "The final cork in the bottle is Terpal. After last harvest we may plan to use a bit more."

So far diseases have been less worrying. "Crops have been growing away from the septoria, so it is not the problem I thought it might be three weeks ago." The farms first wheats only rotation ensures eyespot is rare.

Up to now his wheat fungicide programmes have been triazole/morpholine based. But whole field tests with Amistar (azoxystrobin) fungicide last year and independent trials elsewhere encouraged him to use it quite widely this season. He expects to get all he needs through supplier Technicrop. "I dont anticipate a supply problem".

Last years experiments were all on Buster in neighbouring high-yielding fields. Outputs from his standard programme, from one substituting Amistar at second node only, and one applying it then and at flag leaf were 9.77, 9.9 and 10.54t/ha (3.9, 4.0 and 4.3t/acre) respectively. "They werent replicated trials and it probably wasnt all down to the fungicide. So the results must taken with a pinch of salt. But I am keen to go the Amistar route because we are trying to reduce the number of sprays we need and extend the T1/T2 gap."

Clear candidates for treatment this year are 130ha (321 acres) of early sowings with most potential, mainly on heavier land. Indeed about two-thirds had already had a GS31/32 spray of 0.4-0.6litres/ha, depending on varietal resistance, along with 0.3litres/ha of Agrys (fenpropidin + fenpropimorph) and 0.25litres/ha of Opus (epoxiconazole) to provide an initial clean up by Mar 25. Brown rust is already showing in some Buster.

Mr Mackintosh hopes the mix will keep crops clean until flag leaf when Opus will probably be the main spray choice. "But I shall possibly try Amistar again on about 50ha."

Later sown crops, especially those on the sands which suffer summer drought, are less able to justify the new approach, he says. "But I may be tempted to try a bit even on them to see if it keeps them green longer."

Limited trials information is his main reason for not considering kresoxim-methyl based newcomers Landmark and Mantra. "I havent really looked at them."

Cost relative to morpholines means he plans no more than a look/see amount of this years other main newcomer, mildewicide quinoxyfen (as in Fortress). "I have not seen a lot of trials data."

Mr Mackintosh has been in no rush to apply nitrogen to avoid encouraging unwanted tillers. But signs are that more N is just beginning to be needed. All crops (for feed) had 40kg/ha (32 units) in February.

In the past his total dressing, usually in three splits all liquid, has been about 185kg/ha (148 units/acre), depending on previous cropping and soil indices. Alternate tramline trials backed by combine yield monitoring last year suggest that can be trimmed by 5-10kg this season, he says. &#42

Keeping all the cereal crops happy at The Homme, Ross-on-Wye, is a real challenge this year, says manager Steven Mackintosh. Two management strategies usually suffice – this years variable crops need more like five.

BAROMETER ROUND-UP

Novel fungicides figure in the plans on other barometer farms, but old friends are being relied on for initial treatments.

&#8226 South: The odd season means Patrick Godwin has departed from his normal routine for the wheats and split his first fungicide/growth regulator treatment. First GS31 application on Brigadier, Consort and Riband, where septoria and February-spotted yellow rust are the main targets, is 0.2/0.4litres/ha Pointer/Bravo (flutriafol/chlorothalonil) with Cycocel + Moddus (chlormequat + trinexapac-ethyl) at 1.25 and 0.2litres/ha. "That should take care of things for now. But we will have to go again at GS32 in about 14 days with the same mix." Strobilurins may be tried later but only according to the potential of the crop. "Its no good trying to make a silk purse out of a sowss ear."

&#8226 Northern Ireland: The weather has been against spraying, but Michael Kane is keen to get Barleyquat (chlormequat) on to his wheats, especially those after oilseed rape which are at GS31/32. All recently had 63kg/ha (50 units/acre) of N. He has small amounts of Amistar and Landmark ready for early trials. But the main first fungicide treatment, to deal mainly with septoria, will be a mix of Bravo, Pointer and Opus (epoxiconazole) at 1, 0.5-0.75 and 0.25litres/ha respectively. That mix costs about the same as a half rate of Landmark. "It makes me wonder whether I shouldnt have planned to use more of the newer material."

&#8226 North: Keith Snowball is under little pressure to venture onto his wheats, which include some unusually tall but sparsely-tillered Brigadier. First nitrogen is due about now. "But it will be a while before we need do anything else." Plans include tackling potential eyespot in a crop after oats with new fungicide Unix (cyprodinil).