To present research information available on role of foliar fungicide mixtures with new chemistry against barley LR in a variety with known APR.

• Barley leaf rust (LR) was observed on barley regrowth in the lower Great Southern and South Coast of WA in the summer/autumn of 2016. This contributed to the first observations of infected barley crops in the region in July 2016. All barley varieties including those with Adult Plant Resistance (APR) were under severe disease pressure and responded to application of fungicide.
• The high levels of LR in 2016 and the possibility of barley regrowth in autumn 2017 means a significant LR risk for the 2017 season and fungicide programs for APR varieties should be considered.
• LR is a social disease and all growers should be proactive in eliminating the volunteer barley green bridge. To minimise early onset of LR, the regrowth barley should be eliminated at least 4 weeks before seeding.
• Star of Bethlehem (an alternate host) should be sprayed to eliminate the likelihood of new pathotype developing in the region.
• Selecting varieties with adult plant resistance genes will reduce grain yield loss. However, performance of these varieties against LR is influenced by seasonal weather, time of disease onset, crop agronomy, and is hard to predict season to season. Depending on the LR pressure in the crop they may need early foliar fungicide intervention to reduce development of disease on plants during the growing season.
• Oxford possess two partial resistance genes (Rph20 and Rph24), and under high LR pressure application of foliar fungicides increased yield up to 64 per cent.