22 August 1997

Ear sprays worked well in tough year

EAR sprays on wheat have proved their worth during one of the wettest flowering and grain filling periods for years, with new chemistry performing particularly well.

But difficult-to-control fusarium and blackpoint have hit some crops hard.

"Despite their best efforts, fusarium ear blight is the disease most growers will notice this season," says ADASs Bill Clark. Although affected grains are shrivelled, yield loss is limited thanks to compensatory growth, he notes.

Blackpoint, mainly caused by alternaria, has infected several varieties, especially Hereward. The disease can discolour flour so millers may reject loads, he notes. But good control is largely a fluke. "The infection period may be as short as a few hours, when glumes gape during grain fill."

Although triazole-based ear sprays gave reasonable sooty mould control and should produce bolder, cleaner grain, new strobilurin Amistar (azoxystrobin) was outstanding, says Mr Clark. "Its persistence may also give better blackpoint control."

For eastern barometer grower Philip Godfrey, the role of an ear spray is now is question. In his trials a two-spray programme used straight strobilurins and no ear treatment. Yields were boosted by about 1t/ha and specific weights by 2-3kg/hl this season, compared with a three-spray triazole/morpholine programme which included the ear timing.

Brown Butlins Jim Butchart has seen similar results with strobilurins. "Crops held on longer, and were cleaner and a better colour."

Standard commercial recommendations of 0.3-0.4 litres/ha of Folicur (tebuconazole) worked "reasonably well", he notes. But untreated crops have suffered, notably from sooty moulds. "There are some pretty black-looking crops about."

Colin Myram of East Anglian Cropcare agrees. Yellow rust-prone crops sprayed with Folicur are largely free of sooty moulds, though other varieties treated with Plover (difenoconazole) are brighter. Amistar-treated crops look even better, though fusarium has proved tricky to control regardless of product.

Ear diseases have hit cereals hard this season. But new chemistry has shown much scope for keeping crops bright and bold (above).

EAR SPRAY SUCCESS

&#8226 Triazoles: Reasonable control of sooty moulds – Plover best?

&#8226 Amistar: Good sooty mould control, crops clean.

&#8226 All treatments struggled to control fusarium.

&#8226 Blackpoint common: Amistar may provide some control.