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"Hemileia vastatrix"
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Coffee is not forever : a global history of the coffee leaf rust
\"Coffee Is Not Forever assesses the global spread of a dire existential threat-coffee rust-to a crop consumers take for granted. In departing from commodity histories' usual emphasis on the social and economic, and instead putting ecology at the forefront, Stuart McCook offers the first truly global environmental history of coffee\"-- Provided by publisher.
Book
CORRELATION OF VARIOUS ENVIRONMENTAL FACTORS TO COFFEE LEAF RUST DISEASE AND ITS NATURAL CONTROL
Climate is an important factor in the development of plant diseases. to be able to avoid yield loss due to disease explosion, it is necessary to conduct an in-depth study of climatic factors as a direct and indirect influence. one that can be done is weather data-based forecasting. This method can determine and estimate the likelihood of disease outbreaks in a certain period. In addition, disease forecasting can act as prevention due to pathogen attacks so as to avoid damage and yield loss and maintain the ecosystem of antagonistic fungi in the coffee ecosystem. Agro ecosystem management can encourage the development of antagonistic fungi as pathogen biological agents. Akanthomyces sp. species are widely reported as entomopathogenic fungi. In Indonesia, Akanthomyces sp. was found to be associated with Arabica coffee leaf rust disease. This study was conducted in seven coffee plantation locations in Kalibening District, Banjarnegara Regency, Indonesia. This study detected environmental factors affecting the development of Hemileia vastatrix, predicted its population and determined the antagonistic fungus associated with H. vastatrix, namely Akanthomyces sp. TBK2, by molecular detection.
Journal Article
Exogenous application of salicylic acid to control coffee rust
The exogenous application of salicylic acid can induce plant resistance against pathogens. However, little is known about the potential uses of this bioregulator for controlling coffee diseases. In this study, we assessed the effect of applying salicylic acid (SA – 150 mg L-1) on the management of coffee rust (Hemileia vastatrix) in a 7-year-old coffee plantation with low crop load (651.6 kg ha-1 in 2017). For comparison, plants were sprayed with protectant fungicide (copper hydroxide – CH) and standard fungicides (SF) used by local farmers (boscalid, pyraclostrobin + epoxiconazole, and copper hydroxide). Non-treated plants were included as a negative control. Five monthly applications were performed from November 2016 to March 2017. Rust incidence and severity, defoliation, and growth of plagiotropic branches were evaluated monthly. The activity of catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and total proteins was assessed one day after the first, third, and fifth product applications. Compared to untreated plants, SA reduced the severity and incidence of rust from 36.3 to 54.7%, while CH and SF reduced disease from 31.8 to 54.6% and from 83.8 to 88%, respectively. SA reduced defoliation by 54.1%. SA increased the concentration of CAT, APX, and SOD after the first application. However, this effect was not observed after subsequent applications. Foliar application of SA reduces the severity and incidence of coffee rust and defoliation in plants with a low crop load.
Journal Article
Epidemics and the future of coffee production
In this perspective, we draw on recent scientific research on the coffee leaf rust (CLR) epidemic that severely impacted several countries across Latin America and the Caribbean over the last decade, to explore how the socioeconomic impacts from COVID-19 could lead to the reemergence of another rust epidemic. We describe how past CLR outbreaks have been linked to reduced crop care and investment in coffee farms, as evidenced in the years following the 2008 global financial crisis. We discuss relationships between CLR incidence, farmer-scale agricultural practices, and economic signals transferred through global and local effects. We contextualize how current COVID-19 impacts on labor, unemployment, stay-at-home orders, and international border policies could affect farmer investments in coffee plants and in turn create conditions favorable for future shocks. We conclude by arguing that COVID-19’s socioeconomic disruptions are likely to drive the coffee industry into another severe production crisis. While this argument illustrates the vulnerabilities that come from a globalized coffee system, it also highlights the necessity of ensuring the well-being of all. By increasing investments in coffee institutions and paying smallholders more, we can create a fairer and healthier system that is more resilient to future socialecological shocks.
Journal Article
Monitoring Coffee Leaf Rust (Hemileia vastatrix) on Commercial Coffee Farms in Hawaii: Early Insights from the First Year of Disease Incursion
Coffee leaf rust (CLR, Hemileia vastatrix) is considered the most damaging coffee disease worldwide, causing reduced yields and even plant death. CLR was detected in Hawaii for the first time in 2020, and quickly spread across the state. We initiated a CLR monitoring program in Kona, West Hawaii Island, to track the spread of this new invasive disease across a broad elevational gradient. The goals of the program were to assist growers in the early detection of CLR, to characterize patterns of disease incidence across the region, and to collect information on farm agronomics, management practices, and costs to apply fungicides, all of which can be used to develop Integrated Pest Management (IPM) strategies for this pathogen. We monitored 30 coffee lots in Kona, located between 204 and 875 m elevation. Average CLR incidence remained below 4% early in the season and increased to 36% during harvest. We observed no significant difference in CLR incidence between low-, mid- and high-elevation farms. A significant reduction in the number of leaves per branch was observed at the end of the harvest season, and a significant negative correlation was found between the number of leaves per branch and maximum CLR severity. Mean disease incidence and mean severity were observed to have a significant positive correlation. Incidence increased above threshold levels (5%), despite most growers applying preventative fungicides 3–10 times throughout the season, suggesting that improved coverage and timing of applications is needed along with the addition of systemic fungicides. Our study provides the first insights into CLR disease patterns under the unique and variable conditions under which Hawaiian coffee is grown, and will aid in the development of IPM programs that can be used to sustain Hawaii’s coffee industry under this new threat.
Journal Article
High-Density Chitosan Induces a Biochemical and Molecular Response in Coffea arabica during Infection with Hemileia vastatrix
The coffee industry faces coffee leaf rust caused by Hemileia vastratix, which is considered the most devastating disease of the crop, as it reduces the photosynthetic rate and limits productivity. The use of plant resistance inducers, such as chitosan, is an alternative for the control of the disease by inducing the synthesis of phytoalexins, as well as the activation of resistance genes. Previously, the effect of chitosan from different sources and physicochemical properties was studied; however, its mechanisms of action have not been fully elucidated. In this work, the ability of food-grade high-density chitosan (0.01% and 0.05%) to control the infection caused by the pathogen was evaluated. Subsequently, the effect of high-density chitosan (0.05%) on the induction of pathogenesis-related gene expression (GLUC, POX, PAL, NPR1, and CAT), the enzymatic activity of pathogenesis-related proteins (GLUC, POX, SOD, PPO, and APX), and phytoalexin production were evaluated. The results showed that 0.05% chitosan increased the activity and gene expression of ß-1,3 glucanases and induced a differentiated response in enzymes related to the antioxidant system of plants. In addition, a correlation was observed between the activities of polyphenol oxidase and the production of phytoalexin, which allowed an effective defense response in coffee plants.
Journal Article
The Community Ecology of Herbivore Regulation in an Agroecosystem
Whether an ecological community is controlled from above or below remains a popular framework that continues generating interesting research questions and takes on especially important meaning in agroecosystems. We describe the regulation from above of three coffee herbivores, a leaf herbivore (the green coffee scale, Coccus viridis), a seed predator (the coffee berry borer, Hypothenemus hampei), and a plant pathogen (the coffee rust disease, caused by Hemelia vastatrix) by various natural enemies, emphasizing the remarkable complexity involved. We emphasize the intersection of this classical question of ecology with the burgeoning field of complex systems, including references to chaos, critical transitions, hysteresis, basin or boundary collision, and spatial self-organization, all aimed at the applied question of pest control in the coffee agroecosystem.
Journal Article
Coffee leaf rust assessment: comparison and validation of diagrammatic scales for Coffea arabica
Coffee leaf rust (CLR) is the most important disease in coffee and is caused by
Hemileia vastatrix
. The use of a diagrammatic scale helps people more effectively evaluate rust severity and improves disease measurement by evaluators. Our goal was to develop a new scale with colored pictures and seven disease levels (0; 0.1–1.0; 1.1–2.0; 2.1–5.0; 5.1–10.0; 10.1–25.0; >25.0%) and then compare the severity results of CLR on arabica coffee leaves with those based on three other scales. Three evaluations were performed by ten different evaluators. The first assessment was performed without a scale. On the same day, raters performed four assessments with each of the four diagrammatic scales. The third evaluation was performed at seven-day intervals. We analyzed the statistics with linear regression and Lin’s concordance correlation. The evaluators using the proposed scale improved the precision, accuracy and reproducibility of the evaluations and reduced residual distribution when compared to the evaluators who did not use the proposed diagrammatic scale or who used the other scales. Overall, the proposed diagrammatic scale is a tool that can assist users in producing a disease estimate close to the real value of CLR on arabica coffee leaves.
Journal Article
Global Coffea arabica variety trials reveal genotype-by-environment interactions in resistance to coffee leaf rust (Hemileia vastatrix)
Coffee leaf rust (CLR), caused by the obligate parasitic fungus
, is the most significant constraint in Arabica coffee production worldwide. The disease is ubiquitous, and in severe infections, it can lead to defoliation of coffee plants, impacting yield and quality. The use of resistant varieties is the most cost-effective and sustainable strategy for managing coffee leaf rust. Identifying highly resistant varieties, as well as environments where these varieties perform similarly, is a crucial step in breeding programs.
An international, multi-institutional effort involved the evaluation of 29 varieties, developed by different breeding programs in coffee-producing countries across the globe, for CLR severity under field conditions at 23 sites in Africa, Asia, and Latin America.
The results showed that both the genotype and genotype-by-site interaction were highly significant, indicating that resistance to coffee leaf rust depends not only on the genetic makeup but also varies between sites. In general, varieties with interspecific introgressions were more resistant than the nonintrogressed pure Arabicas. Although stability and overall resistance were correlated, some of the most resistant varieties were not the most stable. Four mega-environments were identified, and sites that were better at discriminating for resistance were found across the three continents.
Overall, this multi-institutional cooperation led to the identification of both locally and globally highly resistant coffee leaf rust varieties, as well as an understanding of their underlying genetics and the further causes of genotype-by-environment interactions concerning coffee leaf rust resistance.
Journal Article
Coffee Leaf Rust in Brazil: Historical Events, Current Situation, and Control Measures
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.
Journal Article