Uredospore movement and observations on the epidemiology of wheat rusts in north-east Australia

Abstract

The overseasoning of wheat rusts (P graminis and P recondita) and the movement of uredospores have been examined in Queensland during three seasons. Wheat rusts over summer on volunteer cereals and certain grasses in the main wheat-growing areas of north-eastern Australia. The local foci of rust appear to be adequate to provide the initial inoculum each season. Large-scale long-distance aerial transport of uredospores is unnecessary in the epidemiology of the diseases and is probably abnormal. The aerial transport of small numbers of uredospores is adequate to distribute genetical novelty rust organisms over vast areas.