Epidemiology of Wheat Leaf and Stem Rust in the Central Great Plains of the USA

Abstract

Wheat (Triticum aestivum L) is grown throughout the grasslands from southern Mexico into the prairie provinces of Canada, a distance of nearly 4200 km. The total area seeded to wheat varies considerably each year; however, from 28 to 32 million ha are planted in the Great Plains of the United States alone. Generally in the central Great Plains, an area from central Texas through central Nebraska, 15 million ha are seeded to winter wheat each year. A wide range of environmental conditions exist throughout this area that may affect the development and final severity of wheat leaf rust (caused by Puccinia triticina L), stripe rust (caused by P. striiformis), and stem rust (caused by P. graminis Pers. f. sp tritici) epidemics and the subsequent reduction in wheat yields. Variation in severity of rust epidemics in this area depends on differences in crop maturity at the time of infection by primary inoculum, host resistance used, and environmental conditions. The interrelationships among time, host, pathogen and environment are complex, and studying the interactions is very difficult. Historically, cultivars with new or different leaf rust resistance genes become ineffective after several years of large-scale production within the Great Plains, and then cultivars carrying new or different resistance genes must be developed and released into production. This is the typical "boom and bust" cycle of the cereal rust resistance genes in the central Great Plains.

Screening For Resistance Against Rust Diseases In Advanced Wheat (Triticum Aestivum L.) Genotypes

“…tritici (pgt) contributes great losses to wheat produce. 2,5,21,22 Here we report our findings for disease intensity (leaf, stem and yellow rusts) on wheat genotypes at various locations (Tables 3-6). Genotypes showed distinct response to different rusts (leaf, yellow and stem rust).…”

Landscape epidemiology of plant diseases

“…Wennström & Eriksson (1997) have shown that the heteroecious rust, Gymnosporangium cornutum, could not survive during winter in its secondary host S. aucuparia and that infection on this species relied on spore dispersal from its primary host Juniperus communis (in this case, spore dispersal is effective up to 50 m away from the primary host). The role of alternative hosts of cereal rusts (leaf rust caused by Puccinia triticina, stripe rust caused by Puccinia striiformis and stem rust caused by Puccinia graminis) on summer or winter survival of the pathogens has been considerably studied in North America but remains unclear (Eversmeyer & Kramer 2000;Line 2002). A well-studied example is the case of the heteroecious stem rust in the USA.…”

Cultivar Mixtures for the Simultaneous Management of Multiple Diseases: Tan Spot and Leaf Rust of Wheat

“…As is characteristic of many residue-borne and soilborne pathogens, the number of generations of P. tritici-repentis generally is low during a growing season and its dispersal gradient is steep (41). In contrast, Puccinia triticina, the causal agent of leaf rust, is typical of many windborne pathogens in that it is highly specialized, polycyclic, and follows a shallow dispersal gradient (10).…”