Australian Mungbean Association

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Halo blight – research update

Inspecting mungbean for halo blight symptoms.


4 March, 2019


Halo Blight Disease in Mungbean – 2019

by Tom Noble, Queensland University of Technology



Leaf symptoms: small water-soaked lesions surrounded by a yellow halo


Life cycle

  • Contaminated seed and infected crop residue
  • Bacterial ooze spread by machinery and water splash (overhead irrigation)
  • Bacteria infect healthy plants through stomata and wounds
  • Cooler temps produce toxin, phaseolotoxin responsible for chlorosis (yellowing)


Managing disease outbreaks

  • Certified, disease free seed. Produced in arid environment's not conducive to bacterial growth, tested molecularly for the presence of disease 1
  • Use of resistant cultivars when available 2
  • Rotate to non-host crop for 2-4 yrs 3
  • Remove weeds and volunteers that may harbour the bacteria 3
  • Minimise movement through fields

1 Currently an AMA approved seed scheme is used in the mungbean industry with the aim to move towards a certified disease free seed scheme

2 Commercial small seeded cultivar Celera II-AU currently has resistance with large seeded varieties in the pipeline

3 See table for a list of halo blight hosts


Effect of halo blight disease

Foliage infection reduces productivity and can result in total crop loss.


Host range of Pseudomonas savastanoi pv. phaseolicola, causal agent of halo blight

Sampling Guide

Information required on samples

  • Cultivar grown
  • Location grown (GPS coordinates)
  • Seed source (Seed crop or retained seed) Inspection report if source was new seed
  • Size of crop (ha) and amount harvested (tonnes) Crop rotation
  • Was halo blight identified in the field previously What growth stage was infection identified
  • Was infected plant material confirmed by a laboratory using plating and PCR


Contact details

Tom Noble, PhD Student

Centre for Tropical Crops and Biocommodities Queensland University of Technology Gardens Point Campus

PO Box 2434

Brisbane 4001 QLD Australia


Tel. +61 422 232 614




This research is funded by the Australian Mungbean Association, Queensland Department of Agriculture and Fisheries (DAF) and the Queensland University of Technology (QUT).


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