A participatory on-farm research project was conducted on five certified organic coffee farms in the Kona district on the Island of Hawaii to evaluate alternative organic-based practices for the management of Coffee Leaf Rust (CLR). Coffee Leaf Rust is a devastating disease of coffee worldwide but has only recently become established in Hawaii over the past few years. Most efforts to date for the management of this disease in Hawaii have focused on chemical controls. However, these have had limited success due to a combination of ideal weather conditions for the disease, highly susceptible coffee varieties, poor soil and plant health, and high costs of labor and imported fungicides. The goal of this project was to reduce the negative impacts of this devastating disease by focusing on improving plant health through increased applications of locally-available fertilizer and microbial amendments. Treatments included: 1) a granular fertilizer composed of fish emulsion and biochar, 2) Indigenous Micro-Organism (IMO) foliar sprays, 3) a combination of both, and 4) an untreated control. These treatments were superimposed on fertilization and management practices already followed by the individual farms. Data was collected monthly on CLR disease incidence (the presence of lesions) and defoliation. We observed considerable variability among the five farms, with some showing reduced disease incidence and defoliation with increased fertilization, and others showing no effect of treatment. With only a single year of data collection, and known differences in weather and management practices among farms, this variation was not surprising and led us to seek an additional two years of funding through the USDA-ARS program, “Systems Approaches to Improve the Production and Quality of Specialty Crops.” Further, we have been asked to submit a full proposal for an additional three-years of funding from the USDA Sustainable Agriculture Research and Extension (SARE) Program.
