RESULTS FROM SMUT EPIDEMIOLOGY STUDIES IN THE HERBERT, MACKAY AND BUNDABERG-ISIS AREAS IN 2007–2008

SUGARCANE smut has continued to spread through infested districts and to previously unaffected regions in Queensland. Epidemiology studies were initiated in late 2006 in the Bundaberg-Childers region and similar work was also undertaken in two other affected production areas (Herbert and Mackay) from the end of 2007. Research focussed on assessing how quickly the disease was spreading to previously disease-free farms within districts and how quickly smut escalated within infested susceptible crops. Disease spread was assessed by regular inspections of the disease-free farms while disease escalation in infested crops was assessed by monitoring diseased stool populations within these crops. Local industry data on newly-infested farms provided additional information on smut spread. Analyses showed that smut was likely to infest all farms within a district two to three years after the first smut finding. The research predicted that all farms in the Herbert would be infested by October 2008, Mackay by February 2009 and the Bundaberg-Childers region by April 2009. Smut escalation in susceptible crops varied considerably; in some cases the 5% infested-stools plough-out threshold was reached 12 months after the first infested stools were found, while in other cases this took 2–3 years. Broad ruleof- thumb recommendations can now be made to farmers and industry in other Queensland production areas.