Coffee Leaf Rust: Some Facts About Coffee’s Worst Enemy

Coffee leaf rust or Roya in Spanish, has been devastating susceptible coffee farms all
over the world. It is an airborne fungal disease caused by Hemileia vastatrix. It survives
particularly on the leaves of the coffee plant. They are transported in water, rain or air,
in the form of tiny spores. They can survive long distances explaining why they can
spread to an entire field.

When leaves are attacked, the plant won’t be able to photosynthesize which is vital for
its growth. These affected coffee plants therefore won’t be able to yield enough coffee
beans.

It is easy to spot coffee leaf rust when it strikes as pale, yellow spots can be found on
the upper surfaces of the leaves. When these spots increase in diameter, there can be
orange uredospores that appear underneath.

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Unlike other rusts which break through the epidermis, these fungi targets the stomata.

There will be powdery lesions in yellowish orange color concentrated on any part of the
leaves. These infected leaves will then drop prematurely.

We have gathered here some facts on coffee leaf rust that you may want to know.

 In 1830, there was a coffee leaf rust epidemic that destroyed the coffee industry
in Ceylon.

 In 2012, a coffee leaf rust epidemic struck Central American crops causing a
billion dollar damage in just 2 years! According to IHCAFE, over 30,000 coffee
plots were affected by leaf rust infections.

 Coffee leaf rust has devastated an area in South America equivalent to the entire
size of Europe which is a whopping 10 million square kilometers. In 2013,
Guatemala grew 40 percent less coffee because of coffee leaf rust.

 The Colombian government spent over 1 billion dollars to combat this disease
as it devastated its primary coffee crop which is the Arabica Coffee.

 It has become too severe that farmers need to decide whether to feed their
families or invest in the ways to mitigate La roya.

 Despite national efforts, as of April 2017, according to IHCAFE, the incidence
level of rust in Honduras was only 6 percent below the level of economic
damage.