Ground Cover Supplement : GC Supplement - Root and crown diseases
2 GROUND COVER ROOT & CROWN DISEASES INTRODUCTION Ground Cover is brought to you by growers and the Australian Government through the publisher, the Grains Research and Development Corporation. Executive Editor: Ms Maureen Cribb, Publications Manager, GRDC; 02 6272 5525; PO Box 5367, Kingston ACT 2604 Managing Editor: Brad Collis, Coretext; 03 9670 1168; fax 03 9670 1127 © All material published in Ground Cover supplements is copyright protected and may not be reproduced in any form without written permission from the GRDC. Design and production : Tim Claeys, Creative Director, Coretext; www.coretext.com.au Advertising sales : Hyde Media; 03 9870 4161; fax 03 9870 4163 Registered by Australia Post Publication No. NAD 3994 By John Sandow MANAGER, CROP PROTECTION, GRDC Improving our understanding and management of root and crown diseases has underpinned substantial increases in profitable grain production across Australia. For example, the introduction of cereal varieties with resistance to cereal cyst nematode is helping combat a disease that was estimated to cost graingrowers $70 million a year in lost production. However, root and crown diseases are resilient foes and graingrowers are constantly facing new challenges. Shifts in disease pressure can be caused by several factors, not least by changes in farming practice. The adoption of no-till provides many benefits, but reducing tillage removes an important control method for fungal root diseases such as take-all and Rhizoctonia. Stubble retention improves moisture retention and beneficial soil microbial populations; but it also provides a host for stubble-borne disease such as leaf rust and crown rot. To ensure we can continue to reap the benefits of these conservation farming practices, the GRDC invests in a suite of projects aimed at improving the management of cereal root and crown disease. Crown rot Estimated to cost the industry $56 million in lost production each year, crown rot is proving a hard nut to crack; but progress is being made. Over the past three years the Crown Rot Initiative has brought together plant breeders, cereal pathologists and cropping systems researchers to execute an integrated research approach to tackle this disease. The latest findings from the initiative are reported in this supplement. Nematodes In 1995, root lesion nematode was the most prevalent root or crown disease reported in a survey of 77 paddocks across the north and central cropping districts of Western Australia. Annual cereal yield losses due to nematodes in WA are in the region of five to 15 per cent and new research has found root ALL ARTICLES ARE BY EMMA LEONARD, UNLESS OTHERWISE STATED ROOT AND CROWN DISEASES ARE PRIORITY RESEARCH TARGETS lesion nematode is not the only culprit. Research is starting to focus on understanding the role of Pratylenchus penetrans and burrowing nematodes. Rhizoctonia While much is understood about the pathology and suppression of Rhizoctonia, it remains a considerable, if intermittent, disease problem across southern and western cropping areas. In low-rainfall districts crop losses of up to 50 per cent are not uncommon, while in other areas the average loss is five to 15 per cent. Currently, GRDC investment is identifying the gaps in our knowledge of this disease and opportunities for improved management strategies under no-till. Extension material targeted at new growers and agronomists is on the drawing board. The potential for biological seed dressings is also being investigated. As with many other crop protection challenges, the GRDC is adopting a two-pronged approach to root and crown diseases: investing in advanced plant-breeding technologies to deliver varieties with improved disease resistance and ensuring that practical disease management solutions are delivered to growers. DNA probes that quantify soil inoculum levels have helped researchers separate the impact of inoculum levels and environment on the expression of seven key soil-borne diseases. With this knowledge, disease risk can be predicted before sowing a crop. A test for crown rot is the most recent addition to this service; tests for stem nematode, bipolaris and pythium are in the pipeline. Australia leads the world in this cutting-edge research, delivering practical on-farm decision-support systems. Another exciting area of work is the 50:50 joint venture between the GRDC and Philom Bios, one of the world's major inoculant companies. This arrangement will result in Australian growers being among the first to access microbial seed dressings that protect crops against root and crown diseases. More information: John Sandow, 02 6272 5525, firstname.lastname@example.org Contributors 2 Dr Michelle Watt, research scientist, CSIRO Plant Industry, ACT; Dr John Kirkegaard, principal research scientist, CSIRO Plant Industry, ACT 5 Dr Stephen Barnett, senior research scientist, SARDI Plant and Soil Health; Dr Simon Antis, research scientist, SARDI Plant and Soil Health; Professor Chris Franco, head of the Department of Medical Biotechnology, Flinders University 6 Dr Alan McKay, leader of diagnostics, SARDI Plant and Soil Health 8 Dr John Heap, senior research scientist, SARDI Plant and Soil Health 9 Dr Ravjit Khangura, plant pathologist, Department of Agriculture and Food, WA; Dr Colin Hanbury, research officer, Department of Agriculture and Food, WA 10 Dr Steven Simpfendorfer, senior plant pathologist, NSW Department of Primary Industries 11 Dr Kirsty Owen, soil microbiologist, Queensland Department of Primary Industries and Fisheries 12 Dr Vivien Vanstone senior plant nematologist, Department of Agriculture and Food, WA 14 Associate Professor Mark Sutherland, Centre for Systems Biology, University of Southern Queensland 16 Dr Sukumar Chakraborty, senior principal research scientist, CSIRO Plant Industry Cover: the GRDC is adopting a two-pronged approach to root and crown diseases: advanced plant-breeding technologies and practical management solutions.
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