YELLOW RUST looks set to be a big threat to wheat crops in high risk areas this season and growers should consider treating seed accordingly, ADAS has advised.

The significant area of susceptible varieties likely to be planted this autumn and large levels of inoculum carried over from last season have raised the risk, said ADAS’s Bill Clark.

“Everyone was surprised last season how much Yellow rust there was on Robigus, but it could have been worse and we were saved by the weather. Very hot weather during May and June stopped the disease in its tracks.”

But Robigus is not the only variety that is susceptible to Yellow rust, he added. Seed treatments will be worth considering for any variety with a 3 or 4 rating. Glasgow, Dickson, Ambrosia and Napier are also susceptible, he noted.

The disease is a particular threat in most eastern parts of the UK, from Kent East Anglia, Northumberland to Scotland, but growers further west may be able to get away without treating seed, he said.

The two main products available are BASF’s Epona (fluquinconazole + prochloraz) and Baytan (fuberidazole + imidacloprid + triadimenol) from Bayer CropScience.

In BASF trials last season, Epona reduced Yellow rust on the flag leaf and leaf one by 60-75%, compared to a single purpose treatment under high infection levels, the firm claimed.