Effectiveness of biofunguisides for the control of rust in coffee seedlings

Abstract

Rust (Hemileia vastatrix) is the most destructive and economically important disease in coffee worldwide, especially in Coffea arabica L. It occurs throughout the plant cycle and chemical, biological and cultural methods are used to control it. integrated management and genetic resistance; although some are ineffective, expensive and polluting. The objective was to evaluate the incidence and severity of rust in coffee seedlings var. Geisha under the effect of different biofungicides. The research was carried out at the El Nueve farm, Santa María Huatulco, Oaxaca; during 2018 in nursery. Different treatments were evaluated: control, products based on microorganisms: Baci-Sur subtilis, Bacit-Sur, Michoderma, Blite Free F-07/Guanobras; the minerals: Copper Oxychloride, Bordeaux Broth, Visous Mineral Broth, Sulfocal and a homeopathic (Nat-Rx), plus some combinations, for a total of 24 treatments. The design was completely randomized with 10 repetitions. The variables to assess incidence were total leaves, healthy leaves and rust damaged. Photographs of damaged leaves were used to assess visual severity using the logarithmic-diagrammatic scale. To assess digitized severity using Adobe Photoshop® CC 2017 software, total leaf area, rust-damaged area, and healthy area were measured. They were analyzed by the Kruskal-Wallis test in SAS software. Significant statistical differences were found between the biofungicides at 150 dda on the incidence of rust (IR), without significant differences in severity. The treatments with the lowest IR were the combination of microorganisms Bacit-Sur+Nat-Rx, Baci-Sur subtilis+Blite FreeF-07/Guanobras and Michoderma+Blite Free F-07/Guanobras.