YIELD LOSSES CAUSED BY SEVERAL ENDEMIC DISEASES IN QUEENSLAND

Only limited sugarcane disease yield loss data have been generated in Queensland, or indeed around the world. This has meant our understanding of the effects, and importance, of diseases on productivity has been partial at best. With disease resistance a major form of disease control, objective data are needed to determine the level of resistance needed to maximise yield while, at the same time, minimising losses resulting from the effects of disease. In the past 18 months, studies were initiated to relate the level of disease yield loss of clones in plant breeding trials to yield. This paper describes research with yellow spot, orange rust and Pachymetra root rot in northern and central Queensland. Losses are shown to be very large (with orange rust in central Queensland causing as much as a 40% yield reduction). This study provides some of the first data on disease-associated yield losses with some diseases. Implications of the results are discussed as well as the potential for extension of the work.