A study released in the Agriculture, Ecosystems & Environment journal has found that growing coffee plants in shade has the potential to reduce coffee leaf rust (CLR).
The study found that through creating dense shade levels, the number of Lecanicillium lecanii (the hyperparasite) grew, reducing the amount of CLR found on the plant.
The study thus proposed that through creating a more favourable environment for the hyperparasite, which was cool and moist, levels of CLR could be managed.
CLR is caused by the fungus Hemileia vastatrix, which causes yellow spots to appear on the surface of the plants with rust-coloured stains on the undersides of the leaves. The disease also results in foliage loss, reducing the amount and quality of coffee crop produced.
“We found that coffee leaf rust was more severe during the dry season, whereas the hyperparasite was more severe during the wet season in two out of three years,” the study states.
“Coffee leaf rust was generally more severe at lower altitudes in the dry season, whereas the hyperparasite was more severe at high altitude.”
The study used Arabica coffee and was carried out between 2017 and 2019 at 60 sites located across south-west Ethiopia. During the dry and wet seasons both the rust and hyperparasites were studied with both landscape and environmental factors taken into account.
Findings from this study provides fungicide alternatives for controlling coffee diseases.