Performance of conventional and biological fungicides for the management of coffee leaf rust and coffee anthracnose

Abstract

Coffee Leaf Rust - Coffee leaf rust, Hemileia vastatrix., is a disease that has severely impacted the major coffee growing areas of the world. The presence of the uredinia reduces photosynthesis capabilities which will lead to premature leaf dropping and this defoliation can kill whole branches. If left untreated, yield can be reduced up to 50% in a growing season. The objective of this project is to collect efficacy and crop safety data to support selection and registration of fungicides that are safe on coffee and effective in the management of coffee leaf rust. In addition, there is an urgent need for systemic fungicides to provide sustained control of the disease throughout the year and to build a sound IPM program to manage fungicide resistance. Overall, Abound significantly reduced incidence of coffee leaf rust compared to the untreated control and Aproach® and Rally® provided good control compared to the untreated plots. Regalia® did not provide good control of coffee leaf rust compared to the control plots. Visual phytotoxicity ratings did not show any injury to coffee foliage, flowers, or berries. Anthracnose - Coffee is a high value commodity in Hawai‘i and diseases are affecting the overall health and productivity of the crop. Anthracnose, Colletotrichum spp., is a common yet easily overlooked problem facing the health of coffee fields across the islands. We sought to determine the efficacy of three fungicides on foliar and berry anthracnose infections. After an inoculation of the coffee trees with the naturally occurring Colletotrichum species, three fungicides were applied over the course of two months in efforts to control the disease. Data was collected in the following months to determine their effects on incidence and severity of disease on the foliage and berries of the coffee trees. Overall, Aproach® Prima significantly reduced incidence of anthracnose compared to the untreated control. Aprovia® Top and Cueva® did not provide good control compared to the untreated plots. Visual phytotoxicity ratings did not show any injury to coffee foliage or berries. More testing of these three products would be recommended to fully estimate their efficacy in controlling anthracnose on coffee.