Research Biologist PhD USDA-ARS-DKI-PBARC Hilo, Hawaii, United States
Abstract Text: Hemileia vastatrix is a fungal pathogen that is the causative agent of coffee leaf rust (CLR), considered the most devastating disease affecting coffee crops around the world. We collected data on CLR incidence, and the methods used by farmers to manage this disease in 27 commercial coffee farms located in the Kona and Ka’u districts of Hawaii Island. Overall, 556 monthly evaluations were conducted in 2022 and 2023. We found a significant increase in CLR incidence during the harvest and post-harvest season. Farm location (district) and the type of sprayer used to apply fungicides did not influence CLR infection. In contrast, factors including elevation, pruning system, and the type of fungicide used had a significant effect on CLR infection. The traditional Kona style pruning system had the highest CLR incidence, while topping and stump pruning in blocks (first year) had the lowest disease incidence. Coffee farms that applied a combination of preventive and translaminar fungicides had significantly lower CLR incidence in comparison to coffee farms that only applied preventive fungicides. Together, these findings will support the development of an integrated pest management strategy for CLR that is adapted to Hawaiian coffee agroecosystems.
