Australian Mungbean Association

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Mungbean Pathology – research update

Fusarium wilt in mungbean.

 

4 March, 2019

 

Mungbean Pathology

by Lisa Kelly, Queensland Department of Agriculture and Fisheries

 

Disease surveillance and diagnostics

During the 2018–19 cropping season, more than 30 mungbean crops were surveyed from southern Queensland and northern New South Wales and more than 30 diagnostic samples were submitted by clients. A dry season with few crops has led to low levels of disease across both regions.

Low levels of disease can still result in high levels of disease next season if conditions become conducive for disease development.

The results showed there was:

  • low incidence (1–5%) of fusarium wilt present in most crops, a few crops in southern Queensland with moderate incidence (10–40%)
  • low incidence of phytoplasma (1–3%) present in most crops
  • low incidence (>5%) of tan spot in four crops in southern Queensland
  • low incidence (1¬–5%) of charcoal rot in most crops
  • no halo blight observed during surveys, however pathogen may be present without producing disease symptoms
  • high incidence of gummy pod due to heat and drought stress.

Powdery mildew symptoms are now starting to show.

Fusarium wilt

Fusarium wilt is caused by species within the F. oxysporum and F. solani species complexes. These are soil-borne pathogens that will persist in the soil for years. Avoid paddocks with a history of disease. Research is underway to better understand the species involved and whether there is any resistance to these pathogens. All of the commercial mungbean cultivars are susceptible, although Onyx-AU, Regur and Celera II-AU have improved levels of resistance to the pathogens. It is estimated that the pathogen can cause more than 70% reduction in yield in affected areas of the paddock. Future research aims to identify alternate hosts of these pathogens.

 

Powdery mildew

Powdery mildew in mungbean is caused by the fungal pathogen, Podosphaera xanthii, however, a second powdery mildew, Pseudoidium sp., has recently been found on both mungbean and black gram. This means that two different powdery mildew fungi are infecting mungbean and black gram in Australia. How widespread is this second powdery mildew? What is the host range of these fungi? Can it be controlled with fungicides? How is it impacting growers? Do we have any host resistance to this second powdery mildew? A PhD study has commenced with University of Southern Queensland to gain a greater understanding of the powdery mildew pathogens infecting mungbean in Australia.

 

Figures 2 (left) and 3 (right). Severe powdery mildew infection, caused by Pseudoidium sp. infecting Jade-AU in Toowoomba, March 2019. Symptoms are found on both upper and lower sides of leaves, on stems and pods.

Diagnostic samples

Specimens should be wrapped in absorbent paper, placed in a zip-locked bag and posted via express post or courier to Lisa Kelly, Plant Pathology, Department of Agriculture and Fisheries, 203 Tor St, Toowoomba Queensland 4350.

For further information please contact Lisa Kelly (details below).

Contact details

Lisa Kelly

Lisa.kelly@daf.qld.gov.au

07 4529 4291

0477 747 040

Acknowledgements

This research is funded by the GRDC projects DAQ00186 and DAQ00210.

 

More information:

www.mungbean.org.au