Diagnosis and management of halo blight in Australian mungbeans: A review

Mungbean (Vigna radiata L. Wilczek var. radiata) is an important food crop cultivated on over 6 Mha throughout the world. Its short duration of 55–70 days, capacity to fix atmospheric nitrogen, and exceptional grain nutritional profile makes the crop a staple for smallholder and subsistence farmers. In Australia, mungbean is grown as a high-value export crop and established as a main summer rotation for dryland farmers. A major threat to the integrity of the industry is halo blight, a bacterial disease leading to necrotic lesions surrounded by a chlorotic halo that stunts and ultimately kills the plant. Caused by Pseudomonas savastanoi pv. phaseolicola, this seed-borne disease is extremely difficult to control, resulting in significant yield loss and production volatility. The challenge of managing halo blight is exacerbated by a wide host range that includes many legume and weed species, and the presence of multiple epidemiologically significant strains. Molecular technologies could play a pivotal role in addressing these issues. This review synthesises current and emerging technologies to develop improved management strategies for the control of halo blight in mungbean.