CHLOROTIC STREAK: A DISEASE REDUCING SUGARCANE YIELDS IN QUEENSLAND

Chlorotic Streak Disease (CSD) was first recognised as a disease more than 70 years ago but the causal agent remains unknown. The disease is transmitted by water (flood and drainage) as well as in diseased planting material. With the recent relatively wet seasons experienced in Queensland, the incidence of CSD has increased significantly. Several aspects of the disease require further research including yield loss, distribution and the identity of the causal agent. Research conducted with funding support from the Sugar Research and Development Corporation (SRDC) has been directed at understanding the relationship between yield loss and varietal resistance. Trials were planted in the Herbert and Tully areas with a range of commercial canes. Large yield losses (up to 60%) were recorded in susceptible varieties where crops grown from diseased planting material were compared with those from healthy plants. Distribution of CSD in the Burdekin was examined through surveys of commercial cane fields. More chlorotic streak was found than expected and an analysis of irrigation water sources showed considerably more CSD-infected fields in those irrigated by channel water (33%) than in those using bore water (4%).