Coffee plantations increase disease pressure on neighboring rainforest plants

A study published in Nature Communications indicates that coffee plantations may alter fungal communities in adjacent tropical rainforests, increasing disease pressure on specific wild plants. Researchers conducted the study across eight farms in Coto Brus, Costa Rica, examining 938 leaves, air samples, and understory seedlings.

The research found a higher incidence of leaf spot disease in wild plant species belonging to the Rubiaceae family—the same family as coffee—near the edges of plantations. This effect decreased as the distance from the plantation increased, reaching up to 100 meters into the forest. Notably, this increased disease pressure was not observed in plants from more distantly related families.

The findings suggest a biological edge effect driven by the movement of organisms rather than environmental factors like light, wind, or humidity. The impact appears most significant when fungi encounter biologically compatible host plants.