Control Barley Scald Early

06 May 2022

PRODUCTION ADVICE & NRM NEWS -  MAY 2022 - AGRONOMY

By John Fowler - Extension Agronomist
P:  03 5881 9933  | M:  0427 079 138  | E:  john.fowler@lls.nsw.gov.au

Scald could cost barley growers a lot of money this season unless it is correctly managed. All barley varieties are susceptible to the disease, especially those sown early (i.e. May) into barley stubbles. The NSW DPI Winter Crop Variety Sowing Guide indicated the degree of susceptibility of most varieties. They range from Planet being MS-S (moderately susceptible) to most varieties being rated S-VS. Failing to control scald in these crops could lead to a 20% yield decline which could lower the crop gross margin by about 40%.

Most foliar diseases, like scald, are of greater concern in wet years. Wet conditions provide an ideal environment for the fungus to infect plants and grow rapidly. Rain splash also assists the spread of spores from infected stubble to fresh leaves.

All barley sown into high-risk sites (i.e. stubble) should have a fungicide seed or fertiliser treatment applied. If this is not practised, then a foliar fungicide will be required by growth stage Z25 – (i.e. fifth tiller formed). If a seed treatment is used, the first fungicide treatment is unlikely to be needed until Z39 (flag leaf emerged). Final treatment will likely be required at Z55 (head 50% emerged from the stem).

High yield potential crops are the most at risk. They are likely to suffer more significant yield loss from uncontrolled foliar disease than low yield potential crops. This is another reason to be proactive with disease management this season.