An outbreak of Fusarium head blight of durum wheat on the Liverpool Plains in northern New South Wales in 1999

In 1999, a serious outbreak of Fusarium head blight occurred in durum wheat crops on the Liverpool Plains of northern New South Wales. Disease incidence in individual crops ranged from 2 to 100%. Gibberella zeae was the predominant pathogen. Analysis of weather records showed that in 1999, wheat flowered in an unusually wet and warm spring thus suggesting weather as a prime factor in the disease outbreak. A field survey showed disease incidence was linked to previous cropping history (particularly maize). Cultivar reaction to the disease was evaluated in a field trial. The durum cultivars Wollaroi and Yallaroi were more susceptible than currently recommended bread wheat cultivars. Seed fungicide dressings and seed grading treatments were evaluated in a series of experiments. Specific gravity grading and carboxin plus thiram seed dressing treatments gave the highest germination and emergence of seed. Carboxin plus thiram was the most effective treatment in reducing G. zeae carryover in seed but did not eliminate it.