ANTIGUA, GUATEMALA — A fungus outbreak is threatening to wipe out Latin American coffee crops and trigger a global coffee crisis.<br /><br />According to the American Phytopathological Society, coffee rust is a disease caused by the fungus hemileia vastatrix, which is characterized by half-smooth spores.<br /><br />Infections usually start on the lowermost leaves of a coffee plant, where the fungus protrude through the stomata on the undersides of leaves.<br /><br />The disease causes powdery yellow-orange lesions to appear on the bright green leaves, making them turn a brownish yellow tinge. These lesions produce more spores, which spread by wind or rain to infect others.<br /><br />Though the fungus doesn't kill coffee plants, it debilitates them by causing leaves to fall out. With its nutrition source gone, the plant is unable to produce coffee cherries.<br /><br />Coffee rust currently has no cure, and while copper-based fungicides have proven effective in controlling infection, chemicals can accumulate and become toxic to the environment.<br /><br />Scientists have also turned to genetic resistance, cross-breeding the rust-susceptible Arabica with a natural hybrid immune to the disease to create a more rust-resistant variety.<br /><br />The resulting beans, though not as high quality as the Arabica, were at least good enough to be accepted by growers and buyers, according to the BBC.<br /><br />However, the World Coffee Research has warned that the fungus is evolving, and may overcome once-immune genes in five to ten years. As of 2017, the Honduran Lempira was no longer resistant, and the natural Timor Hybrid's resistance is also breaking down.<br /><br />Coffee rust had previously wiped out crops in present-day Sri Lanka during the late 1800s. But while that region bounced back by switching to tea production, it's unlikely Latin America will be able to do the same.
