Coffee Leaf Rust in Brazil: Historical Events, Current Situation, and Control Measures

Abstract

In this review of coffee leaf rust (CLR) in Brazil, we report: (i) the historical introduction of CLR in Brazil and the first control measures; (ii) favorable environmental conditions and times of year for the disease; (iii) breeding methods and strategies used for developing CLR-resistant cultivars; (iv) the levels, sources, and types of CLR resistance; (v) the development of Brazilian resistant cultivars; and (vi) chemical and cultural control methods. Most plantations are cultivated with susceptible cultivars, such as those of the Catuaí and Mundo Novo groups. Brazilian research institutes have developed dozens of cultivars with different levels of resistance, and significantly increased the planting of new resistant cultivars. The main sources of CLR resistance are genotypes from Híbrido de Timor, Icatu, BA series carrying the SH3 gene, and Ethiopian wild coffees. High CLR resistance is still observed in Sarchimor and SH3-carrying genotypes. Intermediate CLR resistance is observed in Ethiopian wild coffees and in Sarchimor and Icatu derivatives, where qualitative resistance has been supplanted by races of Hemileia vastatrix. Contact, mesostemic, and systemic fungicides are used for chemical control in Brazil. CLR incidence in Brazil begins to increase after the rainy season onset in November, reaches a peak in June, and remains high until August. Thus, chemical control is typically applied from December to April.

Pseudomonas syringae coffee blight is associated with the horizontal transfer of plasmid‐encoded type III effectors

“…After 48 h, bacterial suspensions were prepared in sterile saline solution (0.85% NaCl) at an OD 600 nm = 0.4 concentration. Inoculations were performed on healthy Catuai Vermelho IAC‐99 seedlings, which is susceptible to bacterial halo blight (Sera et al ., 2022). Seedlings with four pairs of true leaves were used for inoculation with a multi‐needle set immersed in the bacterial suspension (Zoccoli et al ., 2011) using a randomized design with four replicates (each replicate represented by two seedlings and the first and second pairs of leaves being inoculated).…”

The coffee leaf rust pandemic: An ever‐present danger to coffee production

“…Although farmers are at the mercy of the weather, temperature and humidity within coffee plantations and gardens can be modified by the use of shade trees and density of planting. Germination of H. vastatrix spores require 6-24 h of leaf wetness, with an optimal temperature range of 21-25°C (Sera et al, 2022). If these conditions persist, then the time between infection cycles by H. vastatrix (commonly 25-35 days) is shortened.…”

Alternative plant protection strategies for tomorrow's coffee

“…Genetic sources of resistance to coffee leaf rust (CLR), caused by the fungal pathogen Hemileia vastatrix , are today present in most commercial C . arabica coffee cultivars (i.e., Catimores and Sachimores) based on breeding programmes using nine resistance genes called S H 1–9 , from the Timor Hybrid (de Almeida et al, 2021; Sera et al, 2022; Talhinhas et al, 2017; Zambolim, 2016). Wild Ethiopian landraces (i.e., Geisha) also exhibit some level of genetic resistance to CLR (https://varieties.worldcoffeeresearch.org/varieties/geisha).…”