15 June 1998

Question

I HAVE a field of winter wheat, Reaper variety. It is suffering badly from yellow rust. What is the best possible treatment?

Responses

John Purslow, independent agronomist, Norfolk

John Udall, Crop Care, Northamptonshire

Answer 1

John Purslow, independent agronomist, Norfolk

Needless to say, treatment needs to be made at the very first opportunity. Opus (epoxiconazole) is the best triazole choice against yellow rust, but shouldnt leave the crop exposed to other disease. Use a half to three-quarters rate.

A triazole should be enough on its own but, for a belt-and-braces insurance, add a morpholine at a one third rate. Its better not to add Bravo (chlorothalonil) to the mix as it could slow the delivery of the triazole to the infection site.

After spraying, yellow rust can sometimes appear to get worse before it gets better, but then should dry up quite quickly.

Answer 2

John Udall, Crop Care, Northamptonshire

Yellow rust at ear emergence requires quick action. A morpholine is essential, and Fenpropimorph is the best. A triazole with good ear disease control and good rust control would be a good partner e.g Folicur. Also consider a low rate of azoxystrobin for excellent ear disease control.

A mix of all three would be best –
0.5l Corbel + 0.5l Folicur + 0.25l Amistar