Ascochyta blight (AB, Phoma rabiei) is a devastating fungal disease of chickpea in Australia and worldwide. Current control recommendations often fail as the fungus is highly mutable, rapidly eroding host genetic resistance. As a consequence, while host genetic resistance and chemical control are both integral components of an integrated disease strategy for AB, reductions in the overall inoculum load of the pathogen are a key management component to prolong their efficacy.

This project will focus on gaining new knowledge on sources of inoculum of AB that contribute to epidemic initiation and investigate interventions or alternate strategies that can be implemented to reduce inoculum production or carryover. This will reduce the sources of inoculum to initiate disease epidemics and reduce the selection pressure on AB populations. Seed and stubble are the known primary sources of inoculum in Australia, with small amounts of inoculum required for initiation of an epidemic under conducive conditions.

The amount and longevity of inoculum will be quantified from different sources (seed, stubble, alternate hosts) across the main chickpea growing regions to inform potential inoculum carryover. In addition, we will assess potential for novel interventions to limit AB growth and spore release. In combination, this information will be used to investigate potential for new tools to help control AB and inform models that can be used to explore how the distribution of chickpea crops in a landscape affects AB. New information will be provided to growers as part of an integrated management plan.