Foliar diseases inhibit grain filling by reducing photosynthesis, reducing translocation of photo-synthate and increasing respiration of the plant. This results in smaller grain which leads to increased screenings and lower grain yield. Less commonly, foliar diseases can reduce the number of kernels per spike if disease development occurs early in the season. This Ute Guide is designed to assist in making cost-effective fertiliser decisions. To obtain the maximum benefit from investment, fertiliser programs must provide a balance of required nutrients to match yield expectations. To make better crop nutrition decisions, growers need to consider the use of paddock records, soil and tissue tests and trial test strips. This helps build an understanding of which nutrients the crop removes at a range of yield and protein levels.
Foliar diseases inhibit grain filling by reducing photosynthesis, reducing translocation of photo-synthate and increasing respiration of the plant. This results in smaller grain which leads to increased screenings and lower grain yield. Less commonly, foliar diseases can reduce the number of kernels per spike if disease development occurs early in the season.
Most (approximately 75 per cent) grain filling occurs within the first 4-6 weeks after head emergence. It is during this period that it is most important to minimise the severity of disease on the top 3 leaves as they contribute the most photosynthate to grain filling.
Correct disease identification is critical in for the decision to apply foliar fungicides to an infected crop and to aid with selection of the most appropriate fungicide for the disease.
It is important to note that not all disorders on plant leaves are caused by a fungal pathogen. Disorders on leaves may be caused by viral diseases (e.g. BYDV), nutrient deficiency (e.g. Nitrogen) or toxicity (e.g. Boron), or physiological blotching. None of these disorders can be controlled with the application of foliar fungicides.
Purpose of this Ute Guide
This Ute Guide is designed to assist in the identification of key foliar diseases in winter cereals including wheat, barley and oats.
It describes foliar diseases via symptoms on specific plant parts at crop growth stages.
A virulent pathogen (disease-causing organism), a susceptible host and a favourable environment must all be present for disease outbreak to occur. There are differences in the likelihood of damage among the foliar diseases of wheat and barley.
Some diseases are very prevalent, but only rarely cause significant damage, whereas other diseases are rare, yet can cause severe yield loss in certain seasons. It is therefore important to accurately identify the disease when making management decisions.
This Ute Guide will aid rapid identification of foliar diseases in order to aid effectively decision-making.
How to use this Ute Guide
- Ensure you have access to the current crop variety ratings. (See Further Reading)
- Choose the relevant crop stage.
- Choose the relevant plant part.
- Trace down the decision tree via symptom to determine the likely disease.
Any recommendations, suggestions or opinions contained in this publication do not necessarily represent the policy or views of the Grains Research and Development Corporation. No person should act on the basis of the contents of this publication without first obtaining specific, independent professional advice. The Grains Research and Development Corporation will not be liable for any loss, damage, cost or expense incurred or arising by reason of any person using or relying on the information in this publication. The Grains Research and Development Corporation owns the rights to the Ute Guide series.
© GRDC 2016
All work contained in this App is subject of copyright owned by or licensed to the Grains Research and Development Corporation. Apart from any use permitted under the Copyright Act 1968, no part of the work may be reproduced in any form or by any process without prior written permission from the Grains Research and Development Corporation. Requests and enquires concerning reproduction and rights should be addressed to:
Grains Research and Development Corporation
PO Box 5367
Kingston ACT 2604
Telephone: (02) 6166 4500
Facsimile: (02) 6166 4599
Any requests concerning material that does not originate from the Grains Research and Development Corporation will be forwarded to the appropriate copyright owner.
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Technical Editor: Penny Heuston
Photographs for the Foliar Diseases Ute Guide app supplied by:
Hugh Wallwork, SARDI; Bob Rees, QDPI; Andy Barr, University Adelaide; Simon Eyres, DAFWA; University of Adelaide; Trevor Bretag, Victorian Institute for Dryland Agriculture; Robert Loughman, Agriculture WA; Tim Williams; Terry Hahn; Nigel Wilhelm, SARDI; Paul De Barro, UA; Margaret Evans, Natural Resources and Environment Victoria; Vern Gibbs, PIRSA; NJ Grundon, QDPI; Ken Holden, PIRSA; D Ironside, QDPI; Tanveer Khan, Agriculture WA; Mark Newton, PIRSA; Robert Park, Plant Breeding Institute; DAFWA; GRDC; D Sawkins; S Davey; Mohammad Aftab, Victoria Government; Penny Heuston, Heuston Agronomy Services; Greg Platz, QDAF; John Minogue, Ag & General Consulting.
Wallwork, Hugh (2000) Cereal leaf and stem diseases. Grains Research and Development Corporation.
Department of Agriculture and Food (2015) Diagnosing spetoria nodurum blotch of wheat. Government of Western Australia, https://www.agric.wa.gov.au/mycrop/diagnosing-septoria-nodorum-wheat
Department of Agriculture and Food (2016) Managing yellow spot and septoria nodurum blotch in wheat. Government of Western Australia, https://www.agric.wa.gov.au/grains-research-development/managing-yellow-spot-and-septoria-nodorum-blotch-wheat
Department of Agriculture and Food (2016) Oats: leaf diseases. Government of Western Australia, https://www.agric.wa.gov.au/oats/oats-leaf-diseases?page=0%2C0
GRDC (2014) Septoria tritici blotch fact sheet. Grains Research and Development Corporation, Australia, https://grdc.com.au/Resources/Factsheets/2014/02/Septoria-tritici-blotch-fact-sheet
GRDC (2016) Barley yellow dwarf virus fact sheet. Grains Research and Development Corporation, Southern Region, https://grdc.com.au/~/media/E731AF4A67894975A02903961585889F.pdf
GRDC (2016) Sripe rust in wheat: Tips and Tactics. Grains Research and Development Corporation, Northern, Southern and Western Regions, https://grdc.com.au/~/media/Documents/Resources/Publications/Tips-and-Tactics/GRDC_Tips_and_Tactics_Stripe_Rust_WEB.pdf
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