Coffee leaf rust can cause defoliation and decimate production (photo: World Coffee Research)
Cenicafé, the research arm of Colombia’s National Federation of Coffee Growers (FNC) identified six new races of coffee leaf rust not previously characterized in the country, as well as nine variants of the fungus with greater genetic complexity and with different degrees of virulence and aggressiveness. The news prompted Roberto Vélez Vallejo, general manager, FNC to renew calls for farmers to replant with leaf rust-resistant varieties such as Castillo, Cenicafé 1, Castillo zonales, and Tabi.
An epidemic of coffee leaf rust spread through Central America starting in 2012 causing yields to decline significantly. It caused serious yield losses in 2012/2013 and financial losses that ran into several hundred million dollars across the region. Leaf rust fungus, Hemileia vastatrix, attacks the leaves of coffee trees and can cause defoliation. Colombia was particularly hard hit and saw production fall steeply, but a massive replanting program enabled former levels of productivity to be regained. However, coffee leaf rust remains a primary cause of problems in coffee producing countries, with losses of 30-80% in susceptible varieties if timely management is not carried out.
Cenicafé said some of the varieties of leaf rust it discovered show characteristics different from those in other producing countries, which suggests that the fungus evolved in unique ways in Colombia.
“The main recommended management strategy – which is the most economical, sustainable, and efficient – is the use of resistant varieties developed by Cenicafé,” said Hernando Duque Orrego , technical manager, FNC. “The only alternative is chemical control, applying fungicides.” Cenicafé director Alvaro Gaitán said conditions in Colombia are favorable to rust epidemics, throughout the year, in all coffee regions, and at all altitudes, because of the country’s location and geography, the diversity of production systems employed, and very varied patterns of flowering and harvest.
As of today, approximately 84% of the coffee area in Colombia is planted with resistant varieties, a much higher level than in other countries, but resistance does not mean that coffee trees are immune. The remaining 16% of the coffee area in the country is planted with susceptible varieties such as Caturra, Typica, Bourbón, some Catimores, and varietals of unknown origin. Periodic measurement by Cenicafé show that, whilst the average incidence of rust in susceptible varieties is 20% or more, in resistant varieties it is 6% or less. It said the most recent findings regarding new races and variants confirm that coffee leaf rust continues to show significant capacity to evolve and adapt, and potentially, overcome the mechanisms resistant coffee trees use to protect themselves.