In El Salvador, the second half of the year normally provides the best conditions for the disease with infestation decreasing from January onwards. There is also a higher than normal level of infestation exists also in Costa Rica, Guatemala, Honduras and Nicaragua. Coffee rust is extremely hard to assess accurately as to the degree of infestation in any of these areas as rust is always present in some degree. But there are other reasons. This is particularly evident in El Salvador, because rust is at the core of a political dispute for subsidies to the coffee sector.
Procafe, a coffee research foundation, was not getting money from the government and was forced to dismiss most of its employees in July 2012. In September it claimed there was an outbreak of rust and it blamed the government for their lack of support. The Ministry of agriculture calculated the degree of rust infestation in 15%-20% of the area grown to coffee in October 2012, against 70% of Procafe estimate. Although the Ministry of Agriculture dismissed rust as a serious threat, it said it will promote efforts to control it. In Nicaragua the coffee council (Conaface) reduced its estimate for 12/13 by 0.3m bags because of the rust. The equivalent institute in Guatemala estimates a decrease of 0.35m bags and in Costa Rica the decrease would be 0.17m bags. The accumulated total of Nicaragua, Guatemala and Costa Rica is around 0.82m bags according to these official bodies. This should be seen as an upper limit. When it comes to Honduras the effect of the rust on the 12/13 production is has been calculated at 15% by recent visitors to the area. Looking at the rainfall data, there has been very high rainfall in the Eastern Part of El Salvador that borders with the South of Honduras. The Honduran areas of El Morazan/Tegucigalpa and El Paraiso may have been the worst affected. But in other areas of Central America rainfall data seems normal. Even in San Salvador and Santa Ana, in the more important upper half of El Salvador, rainfall seems normal. The impact of the rust in the 13/14 crop will depends on various issues, like the use of fungicides, adequate fertilisation, temperatures and the severity of the rainy season. The disease Hemileia vastatrix is the fungus that causes coffee rust, a disease that is virtually impossible to eradicate and is normally present in some degree in every coffee growing area in the world. It needs winds and rainfall in order to spread (high humidity is not enough). One to two days of continuous rainfall are needed for infection to occur and it is especially likely with temperatures between 15C and 28C, with 22C being optimal. That is why most of the infection occurs during the rainy season. Under the right conditions the disease can spread very quickly. Infected leaves will have bright orange spots that turn brown with a yellow border. An infected tree will suffer from premature defoliation and will direct its energy to produce leaves, not beans. If untreated, coffee rust can end up killing the tree in a few years. In full-sun plantation system like Brazil and Costa Rica, leaves tend to dry faster and thus it is hard for the rust to spread as quickly. They are also easier to spread with fungicides. Trees in higher altitude with cooler climate should also have a much lower level of infection. The depletion of nutrients, especially after a large crop, can increase the likelihood of rust infection. Nutrients (N, P) will normally help the tree recover and lower the chances of infection. Excessive Potassium (K) can actually increase the chances of infection. Copper-based fungicides are very effective against coffee rust, even if the disease cannot be completely eradicated. They are rather expensive and in the case of El Salvador they were in short supply after the rainy season. Many different kinds of Hemileia vastatrix exist worldwide and some of them attacked coffee variants previously thought to be rust-resistant.
The coffee plantations of the Americas were rust-free until the 70’s when an outbreak was recorded in Bahia, Brazil. In less than a decade, the disease has spread all over South and Central America.