How wide is the distribution of Russian wheat aphid in northern NSW and is sorghum an alternative summer host?

Abstract

Key findings • Russian wheat aphid (RWA) was found in northern NSW in 2019 in barley, wheat, durum and barley grass. To date, Tamworth is the most northern site where the aphid has been confirmed in Australia. • Sorghum (Sentinel IG) is an alternative summer host. RWA survival in sorghum in northern NSW depends on climatic conditions. High temperature and humidity can supress RWA survival and reproduction in sorghum. • Millet (Jandowae) is not a suitable host for RWA. • Severe symptoms on young sorghum plants include red tips on the leaves and patches at the place of feeding. • Wheat and barley are the most suitable host and where the highest RWA population developed, followed by oats, sorghum and triticale. • Typical RWA damage is found on its primary hosts (barley and wheat), while little or no symptoms were observed in its secondary hosts (oats, sorghum, triticale).