Compared to stripe and stem rust, leaf rust is potentially the least damaging in susceptible varieties, but in most seasons conditions are conducive for this disease. In most parts of Victoria leaf rust is effectively controlled with resistant varieties, but it can cause problems in areas where susceptible varieties are grown. What to look for. Leaf rust is a relatively easy disease to diagnose as it forms orange- brown pustules that are raised above the leaf surface. Wheat diseases The cereal grain wheat is subject to numerous. Wheat Diseases and Pests: A Guide for Field Identification Excellent color guide from CIMMYT.These pustules can be rubbed off the leaf leaving an orange- brown mark on the finger. The pustules scattered across the leaf surface are circular to oval in shape, and confined chiefly to the upper surface of the leaf (Figure 1). Wheat Diseases and Pests. Home > Agriculture > Pests, diseases and weeds > Plant diseases. List of wheat diseases. This article is a list of diseases of wheat (Triticum spp.) grouped by causative agent. Cereal Pests and Diseases (fourth ed.). Crop pests can be identified through a combination of. Common Insect and Mite Pests. Later in the season, black teliospores develop on mature plants, usually on the under surface of the leaf or on the leaf sheath. These black spores are not of concern. Leaf rust symptoms. Economic importance. In Victoria, severe leaf rust infections can reduce grain yield by more than 2. In recent years losses from leaf rust have been confined to districts where susceptible varieties were grown. Disease cycle. Leaf rust is caused by the fungus Puccinia triticina. Leaf rust, like other cereal rusts, requires a living host to survive from one season to the next. The most important host for rusts in Australia are susceptible volunteer wheat plants growing during the summer/autumn. Rust cannot carry over from one season to the next on seed, stubble or in soil. Wheat varieties susceptible to leaf rust enable inoculum levels to build up on volunteers during the summer and autumn. This can be a problem in seasons following wet summers that favour the growth of self- sown wheat. Plants that become heavily infected with rust in the autumn provide a source of rust for the new season's wheat crop. If these conditions are followed by a mild winter and a warm wet spring, then the chances of a leaf rust epidemic are high. The challenges of maintaining wheat productivity: pests, diseases. Therefore, the chances of a rust epidemic are greatest following a wet summer. In Australia, due to the absence of the alternate host, leaf rust reproduces asexually. This reduces the variability of the rusts in the field and therefore increases the likelihood that resistant varieties will be effective for a long period of time. Rust spores are wind- blown and can be spread over large areas in a short time. The establishment of leaf rust epidemics within a crop is favoured by wet conditions and temperatures of in the range of 1. In most parts of Victoria leaf rust has been effectively controlled because of the widespread use of wheat varieties with resistance to this disease. However, leaf rust occasionally produces new races which are capable of attacking varieties that were resistant when they were first released. These new races occur when a chance mutation occurs in this asexually reproducing fungus. Widespread cultivation of resistant varieties minimises the levels of rust in the environment and reduces the occurrence of new races. It is important that growers are aware of their varieties' disease reaction to leaf rust. Variety resistance ratings are available in the Victorian Cereal Disease Guide (AG1. It is important to use a current disease guide as mutations occur in rust from time to time, and resistant ratings are adjusted accordingly. Cultural practices. Heavy grazing or the use of herbicides during autumn to remove self- sown susceptible wheat will reduce the amount of rust in following crops. However, if spring conditions are favourable for leaf rust development, then even small amounts of rust that survived the autumn can multiply to cause serious yield losses in the spring. Seed treatments. There are seed treatments available which will suppress early infections of leaf rust. Seed treatments are important in susceptible varieties, especially if they are sown early or following a wet summer favouring growth of volunteers. Foliar fungicides. There are a number of foliar fungicides registered for the control of leaf rust in wheat. Fungicides should not be regarded as a substitute for growing resistant varieties. Crops need to be monitored to detect rust early, as timing is critical for the effective control of rust diseases with fungicides. Rust epidemics can be explosive, and once out of control, can be difficult to contain. Like the other rusts it is important to apply fungicides early in the epidemic. If a severe epidemic develops early in the season in a susceptible variety, then it may be necessary to make two applications of fungicide. Rust first appearing after ear emergence is less likely to have a significant impact on grain yield. Further Information. DEPI Information Note Series. Victorian Cereal Diseases Guide (AG1. Decimal Growth Scales of Cereal. DEPI Taking Care with Foliar Fungicides. SARDI Cereal Seed Treatments. The Rust Bust Victorian Winter Crop Summary. Wallwork H (2. 00. Cereal Leaf and Stem Diseases. Plant Breeding Institute. Private Bag 4. 01. Narellan NSW 2. 56. Contact/Services available from DEPIDEPI Field Crop Pathology, Grains Innovation Park,1. Natimuk Rd, Horsham 3. Tel (0. 3) 5. 36. DEPI Customer Service Centre 1. Acknowledgements. This Information Note (AG1. Frank Henry, DEPI Horsham. Financial support by the GRDC is gratefully acknowledged. Last Updated: 1. 6th May 2. ISSN 1. 32. 9- 8.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |