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Wheat Leaf Rust in Canada 2010 Brent McCallum. Wheat Leaf Rust in Canada 2010. Wheat leaf rust, caused by Puccinia triticina , was first observed on spring wheat on June 9 at Winkler Manitoba.
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Wheat Leaf Rust in Canada 2010 • Wheat leaf rust, caused by Puccinia triticina, was first observed on spring wheat on June 9 at Winkler Manitoba. • In commercial spring wheat fields little to no leaf or stripe rust were found, since they were sprayed with foliar fungicide. • Unsprayed trap plots and nurseries had relatively high levels of leaf rust, ranged from 5% to 60% on the susceptible cultivar AC Barrie.
Table 1. Average percentage (%) of the flag leaf infected with leaf rust in surveys from 2001 to 2010 in Manitoba and Saskatchewan *Determined from AC Barrie in unsprayed nurseries and trap plots. Other years were determined from commercial fields.
Wheat Leaf Rust in Canada 2010 – Virulence Phenotypes identified on the 16 North American differentials
*Phenotypes which contain isolates that are avirulent to LrCen.
A subset of 99 isolates representing all the virulence phenotypes were tested on five adult plant differentials and 12 additional seedling resistance genes • Of the adult plant resistance genes tested there was no virulence on Lr22a, only six were virulent to Lr35, but most isolates were virulent to Lr12, Lr13 and Lr37. • There was no virulence to seedling genes Lr19, Lr21, Lr29, and Lr32, virulence was rare to Lr25, and Lr28, intermediate to Lr2c, Lr3bg, Lr23 and common to Lr14b, Lr15, and Lr20.
Wheat Leaf Rust in Canada 2010 • The epidemic was light in farm fields because they were treated with fungicides, but it was relatively heavy in untreated plots. • Common virulence phenotypes were similar to previous years but MLDS increased from 2009 and was the most common. • Populations from eastern Canada were more diverse than from western Canada.
