Microorganisms as biological agents for the management of coffee rust (Hemileia vastatrix Berk & Broome), Madriz, Nicaragua

Abstract

Antagonistic microorganisms represent an alternative for the management of coffee rust (Hemileia vastatrix Berk & Broome), an economically important disease in Nicaraguan coffee plantations. In order to evaluate different biological management alternatives for this disease, an experiment was conducted in the municipality of San Lucas, Madriz, Nicaragua. The experiment involved repeated measurements over time with subsampling in an eight-year-old coffee plantation of the caturra variety with rust presence. The evaluated treatments were: 1) Lecanicillium spp, 2) Trichoderma spp, 3) Bacillus subtilis (Serenade® ASO), 4) Azoxystrobin + Cyproconazole (Amistar Xtra®), and 5) Absolute control (no application). The assessed variables included total leaf count, healthy leaf count, incidence (%), and severity (%). An analysis of variance and Tukey’s mean separation with 95 % confidence were performed. Applications and samplings were conducted approximately every 15 days. The Amistar Xtra® treatment showed the lowest values of coffee rust incidence and severity. However, the best biological product was Lecanicillium spp, which recorded the lowest levels of incidence (15.76 %) and severity (11.33 %) at the last sampling date. Starting from the fifth application, incidence decreased by 74 %, and severity decreased by 66 % compared to the last sampling date, representing a biological alternative for coffee rust management.