Impact of root diseases on pulse crops in Northern and Southern regions

The expansion and intensification of high value pulses in Australia will drive the increased profitability of the Australian grains industry. However, this expansion is threatened by the lack of awareness, from industry, that although often grown as a disease break crop themselves, pulse crops are significantly constrained by soilborne root diseases. In the Southern Region alone, yield losses of ~20 and 30% have been reported due to root diseases in a Grower Advisers’ survey (SARDI, 2019). Growers across the Northern and Southern regions are increasingly reporting patches in pulse crops due to soilborne diseases.

Preliminary work has been undertaken through two recent investments (one by SAGIT and one by GRDC) to determine the potential pathogens causing these yield impacts and their national distribution. In 2020, SAGIT project SUA920, measured yield losses caused by soilborne diseases of pulses, including faba bean and lentil utilizing a mixture of fungicides. Partial control of the soilborne diseases corresponded with yield gains up to 13% in faba bean. High levels of the pathogens, Fusarium spp and Phoma spp were detected yet those with the greatest impact on yield were not determined. In 2019, one research focus of the National Soilborne Disease Interactions (DJP1907-002RMX) investment was to conduct disease surveillance targeting poor performing pulse crops nationally. Several potential pathogens, including Fusarium spp, Phoma spp, Pythium spp and Aphanomyces were diagnosed from root diseases symptoms observed from crops nationally.

An investment to definitively identify the pathogens causing the root disease symptoms and their yield impact is required to allow for the development of sound management strategies for the diseases.

Investment Outcome

By June 2025, information on the pathogens causing root diseases and their yield impact on chickpea, faba bean, mung bean, lupin and lentil will be available to at least 50% of growers / advisers, and GRDC to guide future investment for integrated disease management strategies.

Outputs

Output 1 - By June 2024, develop robust molecular detection and quantification techniques for the key root pathogens associated with root diseases of pulse crops.

Description: Robust molecular methods to detect and quantify priority pathogens (Fusarium spp, Phoma spp, Pythium spp and Aphanomyces) singly and/or in mixed soil samples will be developed to support impact evaluation (Output 2), and soilborne disease pathologists.

Output 2 - Output 2 - By June 2024, correlation of molecular methodology with field sampling, detection and quantification of key root pathogens of pulse crops.

Description: To achieve this output, technical knowledge on sampling methodologies to ensure molecular test outcomes correlate with field detection and quantification developed taking into account interactions with the different environments and soil types.

Output 3 - By June 2026, provide a detailed report on the relative yield and economic impact of soil borne pathogens of pulse crops.

Description: To achieve this output, the molecular techniques developed in Output 1 will be used to establish and conduct field /controlled environment studies to assess the impact of priority pathogens (Output 1) on pulse crops yield, including chickpea, lentil, faba bean, mung bean, field peas and lupin in targeted regions (Northern and Southern Regions).

This will allow for the relative economic impact of each pathogen to be determined, which will support prioritisation for future RD&E efforts and development of disease management strategies. Utilise opportunities during conduct of field trials to evaluate potential management strategies for control of soilborne diseases of pulse crops.