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Crown rot

Fusarium pseudograminearum (cereals), Fusarium culmorum (cereals)

Crown rot (CR) is a significant fungal disease in Australian cereals that can cause yield losses without symptoms and grain quality downgrades without yield reductions. CR restricts the flow of water and nutrients to developing heads when plants are under moisture or heat stress late in the season, resulting in pinched grain or heads without grain, otherwise known as whiteheads. Cereals differ in their tolerance to CR; durum wheat is highly susceptible to crown rot while oats is the most tolerant cereal. However, even the most tolerant bread wheat or barley varieties can suffer up to 40 per cent yield loss under high disease pressure and a hot/dry seasonal finish. The incidence of CR has increased as a result of no-till and tight cereal rotations.
Crown Rot

 
 

Description

CR development is favoured by wet, cool winters and dry, hot springs. Early in the growing season, browning of the outer leaf sheaths at the base of infected tillers may be observed and the plants may be stunted and yellow, or single tillers may have died. In moist conditions, pinkish fungal growth may form on the lower nodes. However, CR can cause yield loss before symptoms become obvious and symptoms are more noticeable when plants are under moisture stress.
 
CR can be confused with take-all disease, which also causes white heads, however CR causes scattered white heads across a paddock while take-all causes white heads on all tillers of a plant. CR is soil and/or stubble-borne and can be present in paddocks on stubble residues at infectious levels for extended periods until the infected stubble is completely decomposed. If disease levels are high and there is low rainfall, it may take up to four years for infected plant residues to decompose to levels safe enough to sow durum wheat.

Control

Management of CR is often difficult as commonly there is more than one soil or stubble-borne disease present which exacerbate CR’s impact. It is also best to use an integrated approach and focus on preventing the build-up of inoculum, so rotation is the most important management tactic. 
 
Management options for CR include:
  • Including two years of non-host crops in a rotation i.e. lupins and peas
  • Using PreDicta® B tests to identify at-risk paddocks
  • Controlling grass hosts both in-crop and in fallow
  • Inter-row sowing between stubble and sow early within a variety’s optimal sowing window
  • Ensuring adequate nutrition, particularly zinc
  • Making variety choices on agronomic fit first and then consider crown rot tolerance
  • Using seed fungicide in combination with the other tools, rather than solely relying on them.
EverGol® Energy is registered for the suppression of crown rot which is characterised by a reduction in seedling damping off, an increase in above ground biomass and reduced early leaf sheath browning. 

Related Product

EverGol® Energy Seed Treatment by Bayer Crop Science


References

Burt, J (2005), ‘Growing rhubarb in Western Australia,’ Department of Primary Industries and Regional Development (DPIRD), https://ausveg.com.au/app/data/technical-insights/docs/f08100.pdf

Department of Primary Industries and Regional Development (DPIRD) (2016), ‘MyCrop: Diagnosing crown rot of cereals’, https://www.agric.wa.gov.au/mycrop/diagnosing-crown-rot-cereals

GRDC (2018), ‘Management of crown rot in southern NSW farming systems’, GRDC Update Papers, https://grdc.com.au/resources-and-publications/grdc-update-papers/tab-content/grdc-update-papers/2018/02/management-of-crown-rot-in-southern-nsw-farming-systems

GRDC (2016), ‘Tips and Tactics: Grow rot in winter cereals, Southern region’, https://grdc.com.au/__data/assets/pdf_file/0029/165917/grdc_tips_and_tactics_crown_rot_southern_web.pdf.pdf?utm_source=website&utm_medium=download_button&utm_campaign=pdf_download&utm_term=North;%20South;%20West&utm_content=Crown%20rot%20in%20winter%20cereals

Moore, K, Manning, B, Simpfendorfer and Verrell, A (Viewed December 2019), ‘Root and Crown Diseases of Wheat and Barley in Northern NSW, Department of Primary Industries NSW, https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0019/159031/root-crown-rot-diseases.pdf