A ProMED-mail post
http://www.promedmail.org
ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org

Date: Wed 1 Mar 2023
Source: Grain Central [summ. Mod.DHA, edited]
https://www.graincentral.com/cropping/researchers-sound-alarm-on-disease-at-goondiwindi-update/


The Australian Grains Research and Development Corporation (GRDC) has issued an alert for a range of cereal diseases, after a "tsunami" of diseases had affected cereal crops in the eastern states in 2022 due to excessively wet conditions. The upcoming winter cropping season carries mammoth disease risks from heavy stubble loads and infected seeds.

Crops and varieties should be chosen carefully and good quality seed used. Timing of fungicide applications and rotating modes of action is also important. Since chickpeas are no longer favoured by farmers in crop rotations, they are encouraged to plant oilseed rape and faba beans rather than wheat after wheat. Volunteer cereals and weeds serving as green bridge for carrying inoculum into this season must be destroyed with herbicides or heavy grazing prior to planting.

Diseases of concern include wheat and barley rusts; crown rot of wheat and durum wheat; white grain; and fusarium head blight (FHB). One registered fungicide is available for FHB, but there is no reliable treatment for crown rot as yet. The major barley diseases in 2022 were powdery mildew and leaf rust. Resistance to powdery mildew has broken down in some of the European varieties with a single resistance gene. Loose smut was an issue in a number of varieties.

New pathotypes are expected to be detected in the next year or so. Exotic incursions of pathogens and their hybrids are making it harder to control leaf rusts and develop varieties resistant against not one, but several genotypes. Pathotypes have been seen to travel extensively within Australia, not just in wet years.

[Byline: Liz Wells]

--
Communicated by:
ProMED

[All diseases mentioned above are caused by or associated with fungi:
- wheat and barley rusts by closely related species and strains of _Puccinia_;
- crown rot of wheat and fusarium head blight of small grain cereals by several species currently or originally classed into the genus _Fusarium_;
- white grain was shown to be associated with _Botryosphaeria zeae_ (ProMED post 20101226.4552), but may also be due to fusarium head blight in other cases;
- powdery mildews of cereals are due to different pathovars of _Blumeria graminis_; f. sp. _tritici_ affecting wheat and triticale; f. sp. _hordei_ affecting barley; f. sp. _avenae_ affecting oats; f. sp. _secalis_ affecting rye;
- loose smut of barley is caused by _Ustilago tritici_.

For more information on the pathogens, see previous ProMED posts in the see also section below and the archives.

Maps
Australia (with states):
https://www.nationsonline.org/maps/australia-political-map.jpg

Pictures
Symptoms of some cereal diseases via:
https://www.ipmimages.org/

Links
List of major diseases and pathogens of wheat:
https://www.apsnet.org/edcenter/resources/commonnames/Pages/Wheat.aspx
List of major diseases and pathogens of barley:
https://www.apsnet.org/edcenter/resources/commonnames/Pages/Barley.aspx
Fungal taxonomy via:
https://www.indexfungorum.org/names/names.asp
- Mod.DHA

ProMED map:
Australia: https://promedmail.org/promed-post?place=8708826,186]

See Also

2022
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Stripe rust, wheat - Australia: (NS,QL) 20220809.8704948
Crown rot, wheat - Australia (northern) 20220318.8702059
2021
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Septoria blotch, wheat - Australia: (SA) strobilurin resistance 20210809.8579912
Powdery mildew, wheat - Australia: new strain, DMI fungicide resistance 20210328.8274657
2020
----
Rhizoctonia, cereal crops - Australia: (WA) 20201218.8027293
Flag smut, wheat - Australia: (WA) alert 20201113.7939679
Barley yellow dwarf, cereals - Australia: (VI) 20201020.7874764
2018
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Barley virus G - Australia: 1st rep (VI) 20181126.6166030
Net blotch, barley - Australia: fungicide resistance (WA) 20180727.5931094
Stripe rust, wheat - Australia: (VI) new strain 20180614.5855829
2017
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Septoria, wheat - Australia: (VI, SA) 20170828.5280388
2016
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Septoria, wheat - Australia: emerging strains 20161031.4598540
and many additional items on cereal diseases in the archives

Website: http://www.isid.org

Published: March 10, 2023