Keep an eye on barley loose smut infection levels prior to harvest

Low levels of loose smut are being observed in some barley crops in Victoria, South Australia and southern New South Wales, particularly Hindmarsh, LaTrobe and Spartacus. Loose smut has been an issue in Hindmarsh in SA and WA in previous years.

Smut infections have been found in crops that have had registered seed treatments applied to seed and good coverage achieved. This is due to these barley varieties being very susceptible to loose smut. Once a crop is infected there is nothing that growers can do this season to stop infections. It is important for growers to estimate infection levels to help decide what to do with infected seed at harvest. This can be done by counting the number of infected heads out of 100 heads in a row.

Spores released at flowering infect florets and the developing grain in the head. This means that next years seed is already infected at harvest. Growers should therefore be cautious of using infected seed from this year to sow in 2017. If retaining infected seed for sowing in 2017 then be sure to use an effective seed treatment. Be aware that new seed will also likely be carrying a low level of infection. You should check what, if any, treatment has been applied to this seed.

Seed treatment tests conducted by SARDI have shown that products containing just triadimenol provide only about 50% control of loose smut in Hindmarsh. Products containing flutriafol and tebuconazole or a low rate of Rancona Dimension (80 mL) allow some infection to persist in crops. If using Vibrance or Rancona Dimension , then higher rates set for rhizoctonia control should be used. The most effective control was provided by products containing carboxin and the new SDHI fungicide Evergol Prime athough even these products may not be 100% effective in all situations.

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