Current status of cereal root diseases in Western Australia under intensive cereal production and their comparison with the historical survey conducted during 1976-1982.

摘要

Two separate surveys of root diseases of cereals in the Western Australian (WA) cereal belt were conducted: the first conducted annually for wheat and barley during 1976-1982 and the second for wheat during 2005-2007. For the 1976-1982 survey, the cereal belt was divided into 15 zones based on the location and rainfall. Sampling was representative of the actual cropping area, with both wheat and barley sampling sites selected by zone as a percentage of total sites. Over 31 000 plants were assessed from a total of 996 fields. Average take-all incidence ranged from 3% in the northern low rainfall zone to 57% in the southern high rainfall zone. Other root diseases assessed included rhizoctonia root rot, fusarium crown rot and subcrown internode discolouration. During the 2005-2007 survey, around 20 000 plants from a total of 210 fields being intensively cropped with cereals were surveyed for take-all, rhizoctonia root rot, fusarium crown rot, common root rot, root lesion nematode and cereal cyst nematode. The 2005-2007 survey results indicated that root and crown diseases prevailed in paddocks frequently cropped with cereals and occurred at damaging levels across all WA cropping districts surveyed. The more recent root disease survey identified that the fungal diseases rhizoctonia root rot and fusarium crown rot and the root lesion nematode were the most serious impediments to intensive cereal production, particularly in the southern region of WA. Comparing the 2005-2007 results with the previous survey of 1976-1982, the relative importance of take-all appears to have declined over the past 30 years.