Stem Rust Ecuador, 29 Feb 2016 (Photo: Charlie Barnes)

A team of scientists from Ecuador, Canada and the USA recently published on the detection of race RRTTF based on samples collected in Ecuador in February 2016. The study led by Dr Charlie Barnes from the Instituto Nacional de Investigaciones Agropecuarias (INIA), Quito, Ecuador has just been published in Plant Disease. Race RRTTF is distinctive by its combined virulence to genes Sr38 and Sr13 and poses a significant threat to wheat production in North and South America as a large proportion of current commercial cultivars are known to be susceptible. The origin of Pgt race RRTTF in Ecuador is unknown, but it is similar to previous isolates of RRTTF from Asia (Pakistan), eastern Africa (Ethiopia), and the Middle East (Yemen). It is unknown whether race RRTTF is a recent long-distance exotic introduction into Ecuador, or a de novo variant of an existing South America lineage that was introduced earlier. Further study is needed to determine how widespread this race is in Ecuador and its potential to migrate to large-scale wheat production areas in South and North America.