Mildew needs robust early treatment

UK - March 21, 2006

Specific mildew control in the T0 spray could give winter wheat growers an extra 10% yield.

September-planted wheat crops are now approaching GS 30, following ideal drilling conditions and an exceptionally mild autumn.  Large areas of mildew susceptible varieties were drilled which, if left unprotected, could suffer a 5-10% yield loss even from moderate mildew levels.

“Despite the recent cold weather there are still a lot of strong forward crops.  Relying on a traditional triazole or triazole/strobilurin combination at the T0 timing won’t protect them against mildew,” says Liz Tomkinson, technical specialist at Dow AgroSciences.

She advises anyone concerned about the threat of mildew to include the specific fungicide Fortress (quinoxyfen) in their first fungicide spray to protect the crop against early infection. 

“With low cereal prices and rising production costs, all inputs must be carefully evaluated for cost-effectiveness and proven reliability,” warns Ms Tomkinson.  “Our market research shows Fortress remains a popular choice because of price, reliability, persistence, ease of tank mixing, and flexible rates appropriate to the problem.” 

Fortress can be used at 0.2 l/ha on highly susceptible mildew varieties, down to 0.1 l/ha on less susceptible ones.  If the disease is already present at high levels, tank-mix with 0.2 l/ha of fenpropimorph or fenpropidin or use Orka (quinoxyfen + fenpropimorph).

The mildewicide remains as good as, if not better, than its competitors.  Last season Dow AgroSciences compared Fortress alone, and in combination with fenpropimorph as Orka, against other specific wheat mildewicides, including newly introduced products, on the mildew susceptible wheat variety Claire.

Results showed that Orka was at least as good as other specific mildewicides, and in many cases better.  All treatments were made at GS30 with mildew present.  Untreated plots showing between 8 and 18 % mildew at assessment five weeks later. 

“The most significant feature was that Orka at 0.5 l/ha, one third recommended rate, gave the same level of mildew control as two competing specific mildewicides at full rate,” says Ms Tomkinson.