Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat worldwide. This review presents basic and recent information on the epidemiology of stripe rust, changes in pathogen virulence and population structure, and movement of the pathogen in the United States and around the world. The impact and causes of recent epidemics in the United States and other countries are discussed. Research on plant resistance to disease, including types of resistance, genes, and molecular markers, and on the use of fungicides are summarized, and strategies for more effective control of the disease are discussed.Résumé : Mondialement, la rouille jaune du blé, causée par le Puccinia striiformis f. sp. tritici, est une des plus importantes maladies du blé. La présente synthèse contient des informations générales et récentes sur l'épidémiologie de la rouille jaune, sur les changements dans la virulence de l'agent pathogène et dans la structure de la population et sur les déplacements de l'agent pathogène aux États-Unis et autour de la planète. L'impact et les causes des dernières épidémies qui ont sévi aux États-Unis et ailleurs sont examinés. La synthèse contient un résumé de la recherche sur la résistance des plantes à la maladie, y compris les types de résistance, les gènes et les marqueurs moléculaires, et sur l'emploi des fongicides, et un examen des stratégies pour une lutte plus efficace contre la maladie.
Symptoms, disease development, and signs of the pathogenThe pathogen causing stripe rust infects the green tissues of plants of cereal crops and grasses. Infection can occur anytime from the one-leaf stage to plant maturity provided plants are still green. Symptoms appear about 1 week after infection, and sporulation starts about 2 weeks after infection, under optimum temperature conditions. The fungus forms tiny, yellow-to orange-colored rust pustules, called uredia. Each uredium contains thousands of urediniospores. A single urediniospore is too small to be seen with the naked eye, but spores on mass are yellow-to orange-colored and powdery. Stripes of uredia or necrosis are not formed on the leaves of seedlings, but as the plants age, generally after stem elongation. Depending on the level of plant resistance and the temperature, various amounts of chlorosis or necrosis appear (hypersensitive response), with or without sporulation. The necrotic stripes or elongated spots that form on leaves of adult plants are distinguishable from spots caused by necrotrophic pathogens. The pathogen of Can. ). stripe rust utilizes water and nutrients from the host plants, which weakens the plants.
Environmental factors affecting stripe rustAs with other diseases, the three factors in the disease triangle are all essential for disease development. However, the development of stripe rust, compared with many other diseases, depends even more on the very specific weather conditions when pathogen inoculum (urediniospores) and susceptible host plants are present. The three most important we...
