Reduction in animal stock numbers, failure of pastures and the need for groundcover is likely to see a substantial increase in the area of cereals planted in mixed farming systems once the drought breaks.
NSW Department of Primary Industries senior research scientist, Dr Steven Simpfendorfer said grass species and grass weeds tend to dominate as legume species decline in pasture mixes over time and with moisture stress.
"These are therefore potentially higher risk paddocks for cereal diseases as the grasses serve as alternate hosts for many wheat and barley pathogens," Dr Simpfendorfer said.
"In all farming systems, extended dry conditions have also increased the longevity of inoculum of stubble-borne diseases such as crown rot in cereals and ascochyta blight in chickpeas.
"This is a result of reduced decomposition of crop residues which harbor the causal fungal pathogens.
"Dry conditions also impact on the lifecycle of some pathogens.
"This results in two and four year old stubble residues being the primary source of inoculum for leaf diseases, such as net blotches in barley, yellow spot in wheat or ascochyta blight in chickpeas."
Dr Simpfendorfer said obtaining good quality seed, in terms of both germination and vigour, could be a further potential issue for sowing in 2020, when the drought hopefully breaks.
"Although this may seem daunting for growers they are urged to discuss these issues with their agronomist and NSW DPI pathologists well in advance of planting," said Dr Simpfendorfer.
"In this strategic way steps can be taken by producers to minimise disease impacts and maximise their profit when recovering from drought."