Thank a snail today: The true heroes protecting our coffee plants (seriously)

Study finds that snails are key to protecting coffee plants from disease

By Angela Garrity, Guest blogger

Heroes come in all shapes and sizes. Coffee lovers may be astounded to hear the secret identity for coffee farmers seeking greener options in pesticide is coming in the form of a gastropod. 

A brown Asian trump snail sits on a green leafiPhoto: The Takeout

Sustainability Times reported that Asian tramp snails, which originated in Asia but are now found around the worod, are lending their appetites to devouring the Hemileia vastatrix fungus (coffee rust disease) on coffee plants. Infected coffee plants bear yellowish blotches that contain spores, ready to scatter and infect other plants. The discolored flora eventually will cause coffee plants to lose its leaves, which prevents the plant’s ability to produce coffee cherries and beans.

Arabica coffee plants are highly susceptible to coffee rust disease. This disease can devastate entire coffee regions, and in result wipes out incomes of coffee farmers. Over 70 percent of Arabica coffee farms have been affected by the disease across Central America, and until now, farmers have been stumped on how to handle it. 

Coffee rust disease currently has no known cure. Farmers applying anti-fungal sprays are concerned by scientists, who say the disease can evolve and become more resistant to anti-fungal spray methods, in the future.

A coffee plant leave with yellow spots, known as Coffee Rust Disease
Photo: Specialty Coffee Association

Scientists from the University of Michigan discovered that the Asian tramp snails feed on the fungus that causes the coffee rust plaque. The researchers set up an experiment by feeding Asian tramp snails with infected leaves. The results showed that about 30 percent of the rust was reduced by the snails after just 24 hours.

Further study is needed before the snails can be deployed to battle the fungus so farmers can save their coffee plants. Zachary Hajian-Forooshani, one of the researchers of the snail study, explains that “the gastropods seem to reduce the number of spores on the leaf, but it’s not clear if the spores can still germinate in the excrement. Also, we don’t know how the effect of the gastropods on coffee leaf rust scales up to impact the pathogen dynamics at the farm or regional scale.”

Sounds like this study will surely move at a snail’s pace, but we have hope.

Related: Study connects coffee preference to genetic makeup