Publication Date

6-1999

DPIRD Collections

Grains and field crops

Publisher

Agriculture Western Australia

City

Perth, WA

Abstract

• Wheat leaf rust (Puccinia recondita f.sp. tritici) is specific to wheat and triticale. A single pathotype (designated 104-1,2,3,(6),(7),11) has dominated in W.A. since 1990. Wheat leaf rust regularly survives the non-cropping summer in varying quantities, usually sufficient to occur at least to a limited extent (particularly in southern regions) each year. The disease develops rapidly between 15 and 22°C when moisture (including dew) is non-limiting. The highest yield increase attributed directly to control of leaf rust in W.A. is 37 per cent. However the disease is synergistically damaging in combination with septoria leaf blotches. In Esperance in 1992 early severe leaf rust in combination with very severe septoria nodorum blotch induced 90 per cent loss. Leaf rust does not affect other cereals and is not hosted by other cereals.

• Wheat stem rust (Puccinia graminis f.sp. tritici) is specific to wheat and triticale. Sporadic outbreaks of stem rust occurred in 1997 (Esperance district) and 1998 (Gnowangerup) on cv. Amery. Stem rust develops optimally between 18 and 26°C and is markedly hampered below 15°C. The higher temperature optimum can result in the most rapid disease development occurring in late spring. The main summer host for wheat stem rust is wheat but barley can host wheat stem rust at high summer temperatures. Barley crops are not normally affected by wheat stem rust. On rare occasions stem rust can cause total crop loss.

• Stripe rust (Puccinia striiformis f.sp. striiformis) has not occurred in Western Australia. Wheat stripe rust mainly infects wheat but can infect barley. A barley grass stripe rust (virulent on a few barley varieties) is now recognised in eastern Australia. Either form could occur in W.A. Optimum temperatures for stripe rust are less than other diseases (most rapid development between 10 and 15°C) resulting in winter epidemics being more common for this disease.

• Barley leaf rust (Puccinia hordei) has emerged as a potential threat to south coastal barley production. In 1997 a new pathotype was detected in W.A at trace levels. This pathotype was similar to the Franklin virulent pathotype occurring in eastern Australia but with additional virulence. The origin of this strain is unknown. In 1998 this pathotype became very severe in a late April sown crop of Franklin. Information generated by the National Cereal Rust Control Program at Sydney University indicates that the new malting variety Gairdner is likely to be similar to Franklin in susceptibility to the new pathotype. The disease is similar to wheat leaf rust in environmental optima and yield losses, causing 20-40 per cent loss when severe.

• Oat stem rust (Puccinia graminis var. avenae) will not attack wheat and wheat stem rust does not attack oats. Oat stem rust, however, occurs on wild oats and volunteer oats which carry the disease over summer. The disease can be very damaging as for wheat stem rust.

• Oat leaf rust (Puccinia coronata) is also known as crown rust. The word 'crown' refers to the shape of a type of spore produced by this fungus and it is not related to the disease symptoms. Oat leaf rust does not infect wheat and wheat leaf rust does not infect oats. The fungus is carried-over on volunteer oats and on wild oats from season to season. The disease can particularly effect oaten hay crops which rely on healthy green leaf area.

Number of Pages

13

Keywords

Department of Primary Industries and Regional Development, fungicides, disease resistance, wheat, barley, septoria, wheat leaf rust

Disciplines

Agricultural Science | Agriculture | Agronomy and Crop Sciences | Plant Pathology

Maps

Maps are not included as part of the complete document download. If this report contains a map, it will be available in the individual parts list below.

Download Complete Bulletin

This file is 3.7 MB. Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Share

COinS