The National Federation of Coffee Growers of Colombia (FNC), through the National Coffee Research Center (Cenicafé, its scientific arm), has warned about the presence in Colombia of races and new, more aggressive variants of the fungus that causes coffee rust .

Studying the disease in susceptible and resistant commercial varieties, and coffee materials of interest in different regions, Cenicafé recently confirmed the presence of four already known rust races and identified six new ones not previously characterized in the country, as well as nine variants of the fungus. of greater genetic complexity and with different degrees of virulence and aggressiveness.

Since 1983, the year in which rust was detected in Colombia, Cenicafé has been identifying more and more races of the fungus, starting with II, from Brazil. Some show characteristics different from those of other producing countries, evidencing the particularity of the changes of the fungus in Colombian coffee growing.

For this reason, the coffee institutions once again urged producers to use resistant varieties as the first line of defense against rust.

“I call on coffee growers to establish or renew their crops with resistant varieties such as Castillo®, Cenicafé 1, Castillo zonales and Tabi, with material obtained from certified seed, either in coffee warehouses, cooperatives or by through the FNC Extension Service ”, said the General Manager, Roberto Vélez Vallejo.

Rust is the main coffee disease in the world (common to all producing countries), with losses of between 30% and 80% in susceptible varieties when proper and timely management is not carried out.

Hernando Duque Orrego, Technical Manager of the FNC, stated: “The main recommended management strategy, which is the most economical, sustainable and efficient, is the sowing of resistant varieties, such as Colombia, Castillo, Cenicafé 1, Castillo zonal and Tabi, developed by the FNC – Cenicafé. Otherwise, the most likely recommendation would be chemical control, applying fungicides on susceptible varieties ”.

The director of the National Coffee Research Center (Cenicafé, scientific arm of the FNC), Álvaro Gaitán explained that in Colombia all conditions are favorable for rust epidemics throughout the year in all coffee regions and altitudes of the country, due to its location geographic, climate, microclimates, topography, diversity of production systems and very varied patterns of flowering and harvest.

Today, just over 84% of the coffee area in Colombia is planted with resistant varieties (which are not immune), an example on a world scale. But still 16% is planted in susceptible varieties such as Caturra, Typica, Bourbón, some introduced Catimores and varietals or unknown materials or without known genetic traceability.

Periodic measurements by the Extension Service and Cenicafé show that, while the average incidence of rust in susceptible varieties is 20% or more, in resistant varieties it is 6% or less, which confirms the strength of these varieties.

However, “the Hemileia vastatrix fungus that causes rust, like any other living microorganism in adverse and diverse environments, can change and mutate in both susceptible and resistant varieties of coffee, its only host. This selection and reaction pressure is a normal dynamic biological process of the fungus, trying to adapt to survive. Hence, little more than 50 races have been identified in the world and variants continue to be identified in different countries ”, stated Carlos Ariel Ángel, researcher at Cenicafé's Phytopathology Discipline.

The most recent findings regarding new races and variants confirm the great capacity of the fungus to co-evolve and adapt to coffee varieties, seeking to overcome the different mechanisms of genetic resistance of plants to achieve more infective and aggressive populations. Some of these results will be presented soon to the coffee and scientific community.

Cenicafé research on the structure of rust populations and the genome, and the development of molecular markers in the DNA of the fungus seek to characterize these new races and variants and identify changes that make the disease more virulent when faced with certain varieties or materials of coffee in different environments.

To face this problem, it is preferable to avoid the establishment of coffee plantations with susceptible varieties, material of unknown origin or without reliable traceability, or with seed collected from commercial coffee lots.

FNC and Cenicafé continue to research strategies for the prevention and integrated management of rust, and are making progress in the composition and development of varieties with durable and diverse resistance to this disease, which at the same time are of high productivity, adaptation and quality for Colombian coffee growers, as part of the More Agronomy, More Productivity, More Quality strategy.