34 IREC Farmers' Newsletter No. 199 — Autumn 2018 RUSSIAN WHEAT APHID DETECTED IN RIVERINA RICE QUICK TAKE l  The discovery of Russian wheat aphid in a South Australian wheat crop in 2016, and its subsequent detection in Victoria, Tasmania and New South Wales, has added a new pest to the ‘wanted’ list for grain growers. l  The response of the Australian Government was to declare the aphid a priority plant pest, as eradication was considered not feasible. Management of the pest is believed possible through a combination of cultural, chemical and biological controls. l  Russian wheat aphid has been detected in cereal crops in the southern irrigation areas and after its discovery in rice crops in late 2017, agronomists are advising grain growers to remain vigilant as the 2018 winter cropping season unfolds. Russian wheat aphid is a major pest of winter cereals on a global scale. When it arrived in Australia two years ago, it was not expected to be seen in rice crops. John Fowler Senior Lands Services Officer - Extension Agronomist Murray Local Land Services, Deniliquin RUSSIAN wheat aphid was found on drill-sown rice seedlings in the Murrumbidgee Valley in early November of 2017. Following this report, a number of Murray Valley drill-sown crops were examined, and all were found to have the aphids present, varying from minor levels to extremely heavy infestations. Populations of Russian wheat aphid in the Riverina crashed (almost completely) after the onset of hot weather. One commercial agronomist said that he saw the aphids persist a little into the late spring–early summer, and he observed some in some aerially sown rice crops. There have not been any reports of the aphids on mature crops, however the possibility of small numbers persisting though the summer in mature crops can’t be ruled out. Russian wheat aphids detected in the early stages of crop growth are mostly wingless. Aphids feed in dense colonies, typically at the base and sheath of the newest leaves. PHOTO: Mark Stevens, NSW DPI