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Hemileia vastatrix is the most important fungal pathogen of coffee and the causal agent of recurrent disease epidemics that have invaded nearly every coffee growing region in the world. The development of coffee varieties resistant to H. vastatrix requires fundamental understanding of the biology of the fungus. However, the complete life cycle of H. vastatrix remains unknown, and conflicting studies and interpretations exist as to whether the fungus is undergoing sexual reproduction. Here we used population genetics of H. vastatrix to infer the reproductive mode of the fungus across most of its geographic range, including Central Africa, Southeast Asia, the Caribbean, and South and Central America. The population structure of H. vastatrix was determined via eight simple sequence repeat markers developed for this study. The analyses of the standardized index of association, Hardy–Weinberg equilibrium, and clonal richness all strongly support asexual reproduction of H. vastatrix in all sampled areas. Similarly, a minimum spanning network tree reinforces the interpretation of clonal reproduction in the sampled H. vastatrix populations. These findings may have profound implications for resistance breeding and management programs against H. vastatrix.

Coffee leaf rust (Hemileia vastatrix) is considered the main disease of conilon coffee (Coffea canephora). Sampling methods aiming at accurate estimation of disease intensity are key for epidemiological studies and management, but there is not one method available for leaf rust of conilon. Thus, the objective with this study was to develop and validate a method to sample leaves to estimate the incidence of rust in conilon coffee plants. Nine within-plant sampling methods for rust incidence (proportion of symptomatic leaves), based on a combination of canopy height of plagiotropic branches, node position and leaf number per branch were established and evaluated during monthly assessment of natural epidemics from October 2011 to April 2013, representing two stages of crop development. The monthly estimated incidence values were compared to the actual rust incidence using linear regression, Lin’s concordance correlation (ρc) and progress curve. The most efficient method was selected based on accuracy and precision. The most accurate and precise sampling method by which to represent the actual incidence was of all the leaves from four plagiotropic branches distributed in the four quadrants in the upper third of the plant. This method was efficient during all crop development stages. Moreover, the estimated incidence progress curve showed the same pattern of temporal distribution as the actual incidence. Thus, a specific method for leaf sampling and estimating the incidence of leaf rust in conilon coffee plants was developed and validated.

Thirteen lines from the coffee germplasm collection of the Adjuntas Agricultural Experiment Substation, lines T-5175 and T-8667 from Costa Rica, and four advanced multilines from the Portugal Research Center for Coffee Rust (CIFC; ‘Centro de Investigación de la Roya del Café de Portugal’) were evaluated for resistance to Hemileia vastatrix and their performance under coffee production conditions in Puerto Rico. The evaluations were conducted in the laboratory and on selected coffee farms. Lines of “Catimor” and “Sarchimor” types were selected based on their reaction to the rust pathogen and excellent agronomic characteristics and named ‘Frontón’ and ‘Limaní’, respectively. Incidence of black beans was examined in red, medium and green beans and was significantly higher in line T-5175, in plantings

The coffee leaf miner, Leucoptera coffeella (Guerin-Meneville), is one of the main pests of coffee (Coffea spp.) in the Neotropical region. Leucoptera coffeella is considered a specialist insect because it develops exclusively within the leaves of the genus Coffea. In this laboratory study, we investigated the oviposition preference and performance of L. coffeella on the coffee leaf rust (Hemileia vastatrix Berkeley & Broome)-susceptible C. arabica cultivars “Red Catuai”, “Red Caturra”, and “Typica”, and resistant cultivars “Costa Rica 95”, “Oro Azteca”, and “IAPAR 59”. Individual (non-choice) and group (multiple-choice) leaves of these cultivars were exposed to mated individual L. coffeella females and the number of eggs laid per leaf was recorded. Oviposition preference was found to be indistinct among the coffee cultivars evaluated. However, larvae and pupal period, and adult body length were significantly affected by the coffee cultivar. These results are discussed in relation to the preference-performance hypothesis and its impact on L. coffeella’s strategy to choose the host plant.

Population genetic studies of Hemileia vastatrix have been conducted in order to describe the evolutionary dynamics of the pathogen and the disease epidemiology as consequence of changes in disease management and host distribution occurred in Peru after the 2013 epidemic. These analyses were performed by sequencing the internal transcribed spacers of the nuclear ribosomal DNA (rDNA-ITS) of H. vastatrix collected from two coffee growing areas in 2014 and 2018. H. vastatrix population showed high haplotype diversity (Hd = 0.9373 ± 0.0115) with a low nucleotide diversity (π = 0.00322 ± 0.00018). Likewise, AMOVA indicated that fungus population has behaved as a large population without structuring by geographical origin and sampling years (FST = 0.00180, P = 0.20053 and FST = 0.00241, P = 0.19693, respectively). Additionally, the haplotype network based on intraspecific phylogenetic analysis of H. vastatrix using Peruvian and NCBI sequences revealed that Peruvian ancestral haplotypes, which were maintained in time and space, would correspond to the reported sequences of the races II and XXII. This re-sult suggests that no substantial changes have occurred through time in Peruvian Hemileia vastatrix population. © 2021, Korean Society of Plant Pathology. All rights reserved. This research was supported by project N? 177-2015 FONDECYT (The National Fund for Scientific and Technological Development) and Universidad Nacional Agraria La Molina, Peru.

The toxicity of J. curcas opens possibilities of breeding program on the production of extracts for controlling the plant pathogens. The H. vastatrix and C. coffeicola fungi causing leaf rust and cercosporiosis diseases, and can be responsible for up to 50% and 30% coffee yield loss, respectively. We developed a biocide for controlling the both fungi, using leaf and stem bark samples from 12 families of J. curcas and submitted them to extraction by ethanol and chloroform solvents. In assays with H. vastatrix, we used 15 μL of spore suspension and 15 μL of the J. curcas extract. Assays with C. coffeicola were performed by using isolates from coffee leaves bearing the disease, grew in PDA medium. For each family, 15 mL of PDA medium and 1 mL of the plant extract were utilized. From the third day on, the mycelial growth was assessed every 24 hours, during 13 days, by evaluating the diameter of the colonies. Data on the antifungal effect of the extracts over C. coffeicola mycelia were subjected to two-way anova. The mean testing was performed as model-identity test, as there was an over-time growth. All 12 extracts of stem bark and leaves of J. curcas, prepared with either ethanol or chloroform, proved to be efficient in controlling H. vastatrix. For C. coffeicola, the extracts inhibited partially the mycelial growth. The extracts that had ethanol as a solvent were more toxic and this result is relevant because ethanol is more accessible to the farmers and the extraction is less expensive.

Background and Objective: Coffee leaf rust disease caused by Hemileia vastatrix resulted in high yield loss and difficult to control. Several chemical fungicides have been used to control this disease. However, the effectiveness of chemical control is low, so it is necessary to find other methods such as biological control. Lecanicillium spp. is well-known as mycoparasite on H. vastatrix uredospores but the study in Indonesia is still limited. This study aimed to collect and investigated the genetic variability of Lecanicillium spp. at various coffee plantations in Indonesia. Materials and Methods: Samples of Lecanicillium spp. were collected from 20 districts in 7 provinces throughout Indonesia. Morphology of colony and conidia were identified by visual examination and by viewed under the light microscope. Genetic variability was conducted using Rep-PCR and clustered with UPGMA. Results: Morphological observation in this study revealed all isolates collected from uredospores of H. vastatrix were similar with Lecanicillium spp. Genetic variability analysis clustered the 80 isolates into eight clusters with their specific characters. Conclusion: Morphological identification in this study showed that 80 isolates of mycoparasite on H. vastatrix belong to Lecanicillium spp. Further study using the molecular technique is needed to identity the species of Lecanicillium.

Hemileia vastatrix is a fungus associated with coffee leaf rust, the most destructive disease of Coffea arabica. The objective of this work was to evaluate the antifungal activity of alcoholic extracts from roots of Baccharis salicina and to determine the metabolites present in these fractions. Antifungal activity was evaluated under in vitro conditions by monitoring the germination ability of H. vastatrix, the coffee leaf rust pathogen. In order to determine the presence of metabolites, chemical characterization of fractions obtained from methanolic root extracts was performed with help of an untargeted metabolomic approach and by using high-resolution mass spectrometry (MS) and MS2 based on direct-injection electrospray mass spectrometry (DIESI-MS) and hierarchical cluster analysis (HCA). Germination percentage was evaluated by leaves fixation technique. The MEBs significantly decreased the percentage of germination of H. vastatrix to levels below 5% as the dose increased. The multivariable analysis confirmed that the distribution of three fractions of methanolic extracts belonged to polyketides, organoheterocyclic compounds, fatty acyls, prenol-lipids, organo-oxygen and farnesene classes. This report comprises the first study of the metabolomic profile and biological activity study of roots from B. salicina against coffee leaf rust pathogen H. vastatrix. © 2021 Friends Science Publishers

9 Páginas Coffee is an important agricultural commodity in the world. However, it is susceptible to Hemileia vastatrix (Hv), an obligatory biotrophic fungus that causes coffee leaf rust (CLR). Natural resistance to rust has been identified in the wild species Coffea canephora and Coffea liberica. These species have been used in breeding programs where interspecific resistant hybrids have been generated. The SH3 gene, derived from C. liberica, has been shown to confer extreme and long-lasting resistance to Hv. A total of 167 accessions of the INIA’s Coffee Germplasm Collection of Peru (INIA-CGC) were screened with 4 markers linked to the SH3 gene. As positive controls, EA67 (C. liberica) and the hybrid S.288 (C. arabica x C. liberica) were used. Separation of PCR products was done by capillary electrophoresis, which allow to discriminate the alleles of each marker. For three markers, specific alleles for either C. arabica or C. liberica species were found. In all cases, S.288 exhibited specific alleles for both species; whereas the INIA-CGC accessions had exclusively C. arabica alleles and EA67 had C. liberica alleles. The BA-48-21O-f marker did not produce PCR fragments for any of the positive controls, suggesting that this marker is not as predictive as the other three to determine the presence of SH3. This work reports the existence of multiple alleles for the Sat244 marker; however, the collection does not have the SH3 mediated-resistance gene. Finally, the utility of capillary electrophoresis as a tool to identify alleles linked to SH3 was demonstrated. 1. Introduction. 2. Materials and methods. 3. Results and discussion. 4. Conclusions. References.

Coffee leaf rust, caused by Hemileia vastatrix, is the most important disease of coffee (Coffea arabica L.) in Mexico. It causes production losses of up to 40% and leads to the use of considerable volumes of synthetic fungicides. The main goals of this research were to identify the temperature, pH, incubation time, and luminosity required for in vitro germination of H. vastatrix uredospores and to evaluate the effect of plant extracts on their germination. Uredospores from coffee plants (var. Caturra) grown in the state of Oaxaca, Mexico, were collected and subjected to treatments consisting of combined levels of T°, pH, and incubation time. The treatments were evaluated in darkness and under low-intensity white light (15 W). Uredospore germination occurred in the absence and presence of light. The highest percentage of uredospore germination was 44.95%, which occurred at pH 5.7, between 18 and 24 °C, and with an incubation time of 24 h. The effect of 30 plant extracts was evaluated in terms of inhibition of uredospore germination. The acetone and ethanol extracts of Tribulus terrestris, Datura ferox, Mansoa alliacea, Ricinus communis, and Acacia farnesiana inhibited 100% of uredospore germination. Thus, plant extracts may contribute to the integrated disease management of coffee leaf rust.

Digitopodium hemileiae was described originally in 1930 as Cladosporium hemileiae; growing as a mycoparasite of the coffee leaf rust (CLR), Hemileia vastatrix, in a sample of diseased leaves of Coffea canephora collected in the Democratic Republic of Congo. No cultures from this material exist. More recently, the type material was re-examined and, based on morphological features, considered to be incorrectly placed in Cladosporium. The new genus Digitopodium was erected to accommodate this species. Interest in fungal antagonists of H. vastarix, as potential biocontrol agents of CLR, led to comprehensive surveys for mycoparasites, both in the African centre of origin of the rust, as well as in its South American exotic range. Among the rust specimens from Ethiopia, one was found to be colonized by a fungus congeneric with, and similar to, D. hemileiae. Pure cultures obtained from the Ethiopian material enabled a molecular study and for its phylogenetic position to be elucidated, based on DNA sequence data from the ITS and LSU regions. Molecular data showed that two members of the recently erected genus Hyalocladosporiella (Herpotrichiellaceae: Chaetothyriales) are congeneric with Digitopodium from Ethiopia and morphologically similar to both D. hemileiae and the two Ethiopian isolates. These isolates were found to be morphologically and genetically identical to H. tectonae, described previously from Brazil. Thus, species of Hyalocladosporiella are re-allocated to Digitopodium here; including D. tectonae, and a novel species, D. canescens, recently found in Brazil growing as a mycoparasite of Puccinia thaliae. The potential use of D. hemileiae and D. tectonae for classical biological control of CLR is discussed.

Essential oils, also known as volatile oils, are substances produced through the secondary metabolism of plants. In this study, we determined the chemical composition and the in vitro and in vivo antifungal activity of the essential oils from four species of Eucalyptus, Eucalyptus citriodora, Eucalyptus camaldulensis, Eucalyptus grandis and Eucalyptus microcorys, against the Hemileia vastatrix fungus. The essential oils from these four species of Eucalyptus were extracted from their leaves by the hydrodistillation technique using a modified Clevenger apparatus. The chemical characterization was performed by gas chromatography coupled with a mass spectrometer detector and by gas chromatography using a flame ionization detector. The antifungal activities of the essential oils against H. vastatrix were studied by evaluating the percentage of spore germination using the microdilution test for in vitro assays. The curative and preventive effects were evaluated in in vivo tests. The principal constituents of the essential oil from E. citriodora were citronellal, citronellol and isopulegol, while E. camaldulensis produced 1,8-cineole, α-terpineol and α-pinene. 1,8-cineole, α-pinene and α-terpineol were obtained from E. grandis and 1,8-cineole, α-pinene and trans-pinocarveol were the principal components in the essential oil of E. microcorys. In vitro and in vivo antifungal activities against the fungus under study were observed for most of the essential oils, except the essential oil from E. microcorys, for which no preventive antifungal activity was observed. Only the curing of infection by the H. vastatrix fungus was observed with this oil.

La roya (Hemileia vastatrix) es la enfermedad más destructiva y mayor importancia económica en el café a nivel mundial en Coffea arabica L. Se presenta en el ciclo de las plantas y para su control se utilizan métodos químicos, biológicos, culturales, manejo integrado y resistencia genética; aunque algunos son inefectivos, caros y contaminantes. El objetivo fue evaluar la incidencia y severidad de la roya en plántulas de café var. Geisha bajo el efecto de diferentes biofungicidas. La investigación se realizó en la finca El Nueve, Santa María Huatulco, Oaxaca; durante 2018 en vivero. Se evaluaron distintos tratamientos: testigo, productos a base de microorganismos: Baci-Sur subtilis, Bacit-Sur, Michoderma, Blite Free F-07/Guanobras; los minerales: Oxicloruro de cobre, Caldo Bordelés, Caldo mineral visosa, Sulfocal y un homeopático (Nat-Rx), más algunas combinaciones, para un total de 24 tratamientos. El diseño fue completamente al azar con 10 repeticiones. Las variables para evaluar incidencia fueron: total de hojas, hojas sanas y dañadas por roya. Se usaron fotografías de hojas dañadas para evaluar severidad visual mediante la escala logarítmica-diagramática. Para evaluar severidad digitalizada con Adobe Photoshop® CC 2017, se midió área foliar total, área dañada por roya y área sana. Se analizaron por la prueba de Kruskal-Wallis en SAS. Se encontraron diferencias estadísticas significativas entre los biofungicidas a los 150 dda sobre la incidencia de roya (IR), sin diferencias significativas en severidad. Los tratamientos con menor IR fueron la combinación de microorganismos Bacit-Sur+Nat-Rx, Baci-Sur subtilis+Blite FreeF-07/Guanobras y Michoderma+Blite Free F-07/Guanobras.

During the Cold War, coffee became a strategically important crop in the global contest between the United States and the Soviet Union. The economies of many US allies in Latin America depended upon coffee. In the Cold War context, then, the coffee leaf rust ( Hemileia vastatrix) became a geopolitical problem. Coffee experts in Latin America, which produced most of the world's coffee, began to prepare for an outbreak. In the 1950s, they built a global network of coffee experts. This network was sustained by US-led Cold War programs that promoted technical collaboration across the Global South, such as Harry Truman's Point Four programs. We explore the network's growth and evolution through one of its central figures, the American plant pathologist Frederick L. Wellman. This network has survived the end of the Cold War and evolved to reflect the new geopolitical context.

Since September 2012, the Jamaican coffee industry has been grappling with the coffee leaf rust (CLR) epidemic caused by the fungal pathogen Hemileia vastatrix. The first widespread outbreak affect...

Arabica coffee (Coffea arabica L.) is a native from Africa, particularly from Ethiopia. Previously of little concern to Ethiopian farmers, coffee leaf rust (CLR), caused by the fungus Hemileia vastatrix, is an emergent disease globally. To update the status of CLR, a large survey was conducted in 405 coffee fields across nine production zones of Oromia and Southern Nations Nationalities and Peoples (SNNP) regions. The disease, evaluated one time during the month of the peak for CLR intensity for each region, was present in every single field; mean incidence and severity ranged from 5 to 86.7% (mean = 35.3%) and 0.22 to 55.5 (mean = 9.09), respectively. A complimentary log-log model was developed to predict mean field severity from mean field incidence. Altitude, a known surrogate variable for temperature, was the main driver of the epidemics. Incidence and severity were highest at the lowland fields, where poorly managed plantations of local varieties grown under open sun were also more dominant. CLR intensity decreased with the increase in altitude at the highlands where well-managed and improved varieties grown under the shade in forest systems dominate the scenario. Our results contribute to increase awareness of a growing problem threatening coffee fields that are still under lower risk, such as at the highlands, particularly if temperatures rise and farmers cut forest to grow plantations of susceptible cultivars. Improving genetic resistance and adoption of best management practices are urgent to prevent the rapid surge of new races and mitigate crop losses currently overlooked by coffee farmers at the lowlands.

Coffee is a source of foreign exchange that plays an important role in the development of the plantation industry. However, many coffee-producing regions have experienced quite detrimental yields in recent years due to the rust of coffee leaves ( Hemileia vastatrix ), a parasitic fungus that reduces yields and that can ultimately kill coffee plants. The use of biochar enriched with Trichoderma can help to improve soil conditions and increase crop production because biochar can increase the availability of N and P. Trichoderma as a biocontrol agent that can help in solving the problem of coffee leaf rust. This study that was conducted at Gondorejo Village, Oro-oro Ombo sub-district, Batu District used a completely randomized design with seven treatments and four replications. The results showed that the application of media with a composition of 1% biochar enriched with Trichoderma supported the growth of Arabica coffee seedlings at the age of 3 months. It can be seen from the available N content, which showed an increase and the number of leaves which had the highest increase among other treatments. This indicated that the composition was sufficient to support good media for the growth of Arabica coffee seedlings.

Pathogen‐associated molecular patterns (PAMPs) are recognized by pattern recognition receptors (PRRs) localized on the host plasma membrane. These receptors activate a broad-spectrum and durable defense, which are desired characteristics for disease resistance in plant breeding programs. In this study, candidate sequences for PRRs with lysin motifs (LysM) were investigated in the Coffea arabica genome. For this, approaches based on the principle of sequence similarity, conservation of motifs and domains, phylogenetic analysis, and modulation of gene expression in response to Hemileia vastatrix were used. The candidate sequences for PRRs in C. arabica (Ca1-LYP, Ca2-LYP, Ca1-CERK1, Ca2-CERK1, Ca-LYK4, Ca1-LYK5 and Ca2-LYK5) showed high similarity with the reference PRRs used: Os-CEBiP, At-CERK1, At-LYK4 and At-LYK5. Moreover, the ectodomains of these sequences showed high identity or similarity with the reference sequences, indicating structural and functional conservation. The studied sequences are also phylogenetically related to the reference PRRs described in Arabidopsis, rice, and other plant species. All candidates for receptors had their expression induced after the inoculation with H. vastatrix, since the first time of sampling at 6 hours post‐inoculation (hpi). At 24 hpi, there was a significant increase in expression, for most of the receptors evaluated, and at 48 hpi, a suppression. The results showed that the candidate sequences for PRRs in the C. arabica genome display high homology with fungal PRRs already described in the literature. Besides, they respond to pathogen inoculation and seem to be involved in the perception or signaling of fungal chitin, acting as receptors or co-receptors of this molecule. These findings represent an advance in the understanding of the basal immunity of this species.

The use of resistant cultivars is the most effective strategy for controlling coffee leaf rust caused by the fungus Hemileia vastatrix. To assist the development of such cultivars, amplified fragment-length polymorphism (AFLP) markers linked to two loci of coffee resistance to races I and II as well as pathotype 001 of H. vastatrix were converted to sequence-characterized amplified region (SCAR) and cleaved amplified polymorphic site (CAPS) markers. In total, 2 SCAR markers and 1 CAPS marker were validated in resistant and susceptible parents as well as in 247 individuals from the F2 population. The efficiency of these markers for marker-assisted selection (MAS) was evaluated in F2:3 and backcross (BCrs2) populations genotyped with the developed markers and phenotyped with race II of H. vastatrix. The markers showed 90% efficiency in MAS. Therefore, the developed markers, together with molecular markers associated with other rust resistance genes, were used for F3:4 and BCrs3 coffee selection. The selected plants were analyzed using two markers associated with coffee berry disease (CBD) resistance, aiming for preventive breeding. MAS of F3:4 and BCrs3 individuals with all resistance loci was feasible. Our phenotypic and genotypic approaches are useful for the development of coffee genotypes with multiple genes conferring resistance to coffee leaf rust and CBD. Made available in DSpace on 2022-01-27T01:59:16Z (GMT). No. of bitstreams: 1 marker-assisted-pyramiding.pdf: 22779626 bytes, checksum: 7a76b7c036947b04bf1229d56a0e8c4e (MD5) Previous issue date: 2021

International audience; Diversified coffee agroforests modify microclimate conditions in comparison with monocultures, impacting the success of significant plant pathogens, such as Hemileia vastatrix, which causes coffee leaf rust (CLR). However, research is often limited to the dichotomous analysis of shaded agroforestry systems or unshaded monocultures, often overlooking the nuanced effect of shade tree trait diversity. Our study aims to determine the cumulative effects of shade tree canopy architectural characteristics and leaf functional traits in biodiverse agroforests on microclimate modifications and CLR incidence. We measured plot-level microclimate conditions (air temperature, relative humidity, leaf wetness duration, throughfall kinetic energy) in three single-stratum and two double-strata shade tree canopy treatments, including Erythrina poeppigiana, Terminalia amazonia, and Chloroleucon eurycyclum. Commonly reported canopy characteristics and leaf traits were compared to average microclimate conditions and CLR incidence levels. We found that shade tree trait expression significantly explained most microclimate conditions, and that two key shade tree traits (canopy openness, leaf area) significantly explain CLR incidence levels (R-2 = 0.211, p = 0.036). Our results highlight the differences in microclimate conditions and CLR incidence among biodiverse agroforests, as well as the important explanatory power of shade tree traits. Specific effects of shade tree traits on pathogen dynamics can directly inform agroforestry system design (i.e., shade tree species selection) and sustainable coffee farm management practices (i.e., pruning practices).

Crop health management systems can be designed according to practices that help to reduce crop losses by restricting pathogen development and promoting host plant growth. A good understanding of pathogen and host dynamics, which are interdependent, is therefore needed. In this article, we used a holistic approach to explain the behavior of coffee leaf rust (CLR), a major coffee disease. We monitored coffee plant and CLR dynamics simultaneously in plots under different disease management and agroforestry systems. Diseased leaves were also collected to characterize inoculum stock and rust life stages (latent rust area, area with uredospores, necrosis due to rust) through picture analysis. We used structural equation modeling to obtain an overview of CLR pathosystem functioning on a plant scale. This overview integrates processes such as disease dilution by host leaf renewal, direct and indirect effects of fruit load on CLR development, antagonistic effects of shading depending on rust life stages, the tonic effect of copper-based fungicides on leaf retention, and effects on rust life stages depending on fungicide types. From our results, we also deduced that the inoculum stock could be calculated in unsprayed plots from the rust area with uredospores, with uredospores at 58 × 103 cm−2, on average.

Small Peruvian coffee producers face low yields per hectare, caused mainly by recent rust outbreaks and by natural crossing of coffee varieties, which are sown without specific order. Coffee rust has drastically reduced areas of susceptible but high-quality cup varieties as caturra, pache, and nacional, which have been replaced by others with high grain weight, but low-quality cup. This study aimed to determine the rooting capacity of sprouts subjected to different concentrations of indole-3-butyric acid (AIB) in three varieties of Coffea arabica, in the San Martin region, Peru. The most appropriate sprout rooting characteristics allowing to propagate rust-tolerant C. arabica plants were evaluated, under the effect of four doses of AIB (0, 1000, 2000, and 3000 ppm) in three coffee varieties (caturra, pache, and nacional), using microtunnels as rooting environments. A completely randomized design, consisting of three repetitions per treatment and six sprouts per repetition, was used. At the end of 50 days, the best rooting result (89%) was obtained with a dose of 2000 ppm of AIB in the caturra variety. The overall results are successful, since there is a conversion rate of sprouts into useful seedlings of more than 85%, if proper handling conditions are implemented. This method of propagation of rust-tolerant C. arabica sprouts by microtunnels enables a mass production of seedlings. The validation of these results could lead to the establishment of entire rust-tolerant coffee farms.

One of the objectives of integrated production (IP) are rationalizing the use of pesticides. For conilon coffee (Coffea canephora), a coffee leaf rust (Hemileia vastatrix) management system based on IP principles needs to be proposed and validated. Thus, this study aimed to quantify the economic and environmental effects of rust management based on disease monitoring for decision-making regarding fungicide use in conilon coffee (integrated coffee production, ICP-Conilon). The ICP-Conilon system was compared with the conventional rust management system (CS) based on a fixed schedule of fungicide application by delineating two plots of C. canephora clonal fields. The incidence of leaf rust in the plants from each clone was quantified monthly and, in the ICP-Conilon plots, systemic fungicide was applied only to the clones/planting rows with monthly disease incidence of ≥5%. The ICP-Conilon system resulted in an average reduction of 71.3% in the fungicide volume applied/ha/year, compared to that in the CS plots. Thus, it was possible to reduce, on average, 21% of the rust management cost in clonal conilon coffee plantations.

Providing adequate nutrition to coffee plants is required to maintain plant health. The effect of five doses (0.05, 0.25, 0.50, 1.0, 2.0 and 4.0 mg L−1) of boron (B), zinc (Zn) and manganese (Mn) on the severity of rust on coffee plants grown in nutrient solution was evaluated. Micronutrients were supplied to seedlings having two pairs of fully developed leaves. The seedling plants were inoculated with spores (106 ml−1) of the coffee rust pathogen (Hemileia vastatrix). Five assessments of the severity of the rust symptoms were made starting on the 43rd day after inoculation. The area under the disease progress curve for severity (AUDPCS) was calculated. There was a statistical difference in AUDPCS (p

La roya anaranjada (Hemileia vastatrix Berk. & Broome) es la principal enfermedad del cultivo del café, y ante la necesidad de disminuir las pérdidas que ocasiona, se han implementado alternativas ecológicas para su control y bajo este concepto esta investigación tuvo como objetivo cuantificar el efecto de cuatro preparados homeopáticos y caldo bordelés al 0.5% en la severidad, infestación foliar y defoliación causadas por este hongo, el experimento se realizó en el Centro Regional de Oriente de la Universidad Autónoma Chapingo en Huatusco, Veracruz, México, de septiembre a noviembre de 2014, donde se asperjaron los homeopáticos cada semana durante 60 d, contando con cuatro repeticiones/árboles por tratamiento en un diseño de bloques completos al azar. El caldo bordelés al 0.5% se aplicó dos veces durante 60 d y a los árboles testigos no se les realizó ninguna aplicación. A los 60 d se registró la severidad en 10 hojas por árbol y a los 30 y 60 d se cuantificó la infestación foliar y la defoliación. Los resultados mostraron que no se afectó la severidad a los 60 d ni la infestación foliar a los 30 d, el polifármaco de plantas (mezcla de 72 preparados homeopáticos antiestresantes y de enfermedades, nutrientes, plagas y plantas de importancia agrícola)/212 Centesimal Hahnemanniana, disminuyó 49.75% la defoliación a los 30 d y la mezcla de homeopáticos redujo 26.65 y 45.06% la infestación foliar y defoliación a los 60 d. La mezcla de homeopáticos permite proteger a la planta más que manejar o eliminar al patógeno, es una alternativa ecológica y orgánica para resolver la contingencia actual de la roya del café.

Diseases of the coffee plant can be effectively managed via well-balanced nutrition. This study assessed the effect of nitrogen and potassium fertilizers on the intensity of coffee (Coffea arabica) rust (Hemileia vastatrix) under greenhouse conditions. The susceptible cultivar New World 376/4 was used as the test species. Treatments included five N rates (3, 7, 11, 15 and 19 mmol L−1) with five K rates (3, 5, 7, 9 and 11 mmol L−1) in a 5 × 5 factorial design, for a total of 25 treatments and three replications with each treatment involving two plants growing in a nutrient solution. The completely randomized experimental design permitted evaluation of N and K on rust incidence and disease severity. The portion below the severity progress curve (AUDPCS) was calculated. Disease severity increased 16.48% with a dose of 7 mmol N L−1 and 11 mmol K L−1. There was an interaction of N with K in the AUDPCS and dried plant mass occurred. The AUDPCS (42.00) was lower when the next dose used was a combination of 19:07 mmol L−1 of N and K. A significant negative correlation was seen with the dry mass of the coffee seedlings.

Leaf rust disease caused by Hemileia vastatrix fungus may become an important issue on highland coffee (Coffea arabica) especially related to the progressive increase in terms of global temperature. A research aimed at evaluating the mineral composition of some rusted coffee leaves from a single clone S 795 was carried out in Andungsari Experimental Station, Indonesian Coffee and Cocoa Research Institute. A single block experiment was situated at 1451 m asl. The intensity of rust spot in the leaves were identified, and estimated to correspond with the score of 5 to 7 out of 10. The difference in the nutrient status between normal and rusted leaves were statistically evaluated by comparing the mean values using unpaired t-test. The leaf analysis shows an optimal range for potassium (K), calcium (Ca), magnesium (Mg) and silicon (Si). Silicon distribution exhibits a high vari- ability with coefficient of variation (CV) around 30%, while K is slightly lower with CV less than 10%. Principal component analysis shows that Ca, Mg and K may have explained the most variation in the original variables as defined by PC1 (54.76%), PC2 (23.22%), and PC3 (14.01%). The rusted leaves are associated with Ca and Si while normal leaves are associated with K. A considerable high of K may explain for the depression of Ca in normal leaves which is, however, associated with an antagonism between these two minerals. The ratio of has a negative correlation with Ca, and may show a potential as an indicator for leaf mineral evaluation in the context of Hemileia vastatrix fungus infected coffee.

The livelihood of at least 120 million people worldwide depends on the coffee supply chain. Coffee rust is among the main diseases that attack the coffee plant and is caused by the Hemileia vastatrix fungus at temperatures between 10 - 30° C. Coffee rust infestation leads to production losses of over $1 billion annually worldwide. Coffee is the second largest traded commodity worldwide, with about $100 billion in volume traded annually. Understanding if there is a relationship between Temperature, Rainfall, Rust, Production and Futures coffee rust variables is important. This research offers the first known quantitative framework for describing and visualizing the correlation between coffee rust, amount of coffee produced and futures prices..

International audience; This paper deals with the problem of modelling and optimal control of the coffee leaf rust (CLR) in a coffee plantation. We first formulate and analyze a mathematical model for the propagation of CLR with impulsive effect, which represents the non-production period of coffee. Then, the CLR control is formulated and solved as an optimal control, showing how a biological control strategy can be implemented in a coffee plantation to reduce the damage caused by CLR, therefore increasing the coffee production. Numerical simulations are performed to illustrate and validate the theoretical results.

The genus Cryptococcus is well known for its two species —Cryptococcus neoformans and C. gatii— that are etiological agents of cryptococcosis, an important fungal disease of mammals, including humans, and which is particularly common in immunocompromised patients. Nevertheless, Cryptococcus is a large and widely distributed genus of basidiomycetes occupying a broad range of niches, including mycoparasitism. One such mycoparasitic species is Cryptococcus depauperatus, which was firstly mistakenly described as a pathogen of scale insects under the name Aspergillus depauperatus. The “Aspergillus” conidiophores were later shown to be basidia of a Cryptococcus and the new combination C. depauperatus was proposed. Additionally, instead of an entomopathogen, the fungus was found to be a mycoparasite growing on the entomopathogen Akanthomyces (Lecanicillium) lecanii. Recently, during surveys for mycoparasites of coffee leaf rust (Hemileia vastatrix) in the context of a biocontrol project, white colonies covering rust pustules were observed in Cameroon. Upon close examination, instead of a member of the “white colony forming complex” of Ascomycetes, commonly collected growing on H. vastatrix, such colonies were found to represent a basidiomycete fungus with basidia-bearing chains of basidiospores, typical of the genus Cryptococcus. Morphological and molecular evidence was generated supporting the identification of the fungus on rust pustules as C. depauperatus. This is the first record of C. depauperatus from Africa and of its association with coffee leaf rust.

Chitosan is a natural polymer, and its biological properties depend on factors such as the degree of deacetylation and polymerization, viscosity, molecular mass, and dissociation constant. Chitosan has multiple advantages: it is biodegradable, biocompatible, safe, inexpensive, and non-toxic. Due to these characteristics, it has a wide range of applications. In agriculture, one of the most promising properties of chitosan is as an elicitor in plant defense against pathogenic microorganisms. In this work, four kinds of chitosan (practical grade, low molecular weight, medium molecular weight, and high-density commercial food grade) were used in concentrations of 0.01 and 0.05% to evaluate its protective effect against coffee rust. The best treatment was chosen to evaluate the defense response in coffee plants. The results showed a protective effect using practical-grade and commercial food-grade chitosan. In addition, the activity of enzymes with β-1,3 glucanase and peroxidase was induced, and an increase in the amount of phenolic compounds was observed in plants treated with high-molecular-weight chitosan at 0.05%, therefore, chitosan can be considered an effective molecule for controlling coffee rust.

Coffee (Coffea spp.) represents one of the most important sources of income and goods for the agricultural sector in Central America, Colombia, and the Caribbean region. The sustainability of coffee production at the global and regional scale is under threat by climate change, with a major risk of losing near to 50% of today’s suitable area for coffee by 2050. Rain-fed coffee production dominates in the region, and under increasing climate variability and climate change impacts, these production areas are under threat due to air temperature increase and changes in rainfall patterns and volumes. Identification, evaluation, and implementation of adaptation strategies for growers to cope with climate variability and change impacts are relevant and high priority. Incremental adaptation strategies, including proper soil and water management, contribute to improved water use efficiency (WUE) and should be the first line of action to adapt the coffee crop to the changing growing conditions. This research’s objective was to evaluate at field level over five years the influence of fertilization with calcium (Ca+2) and potassium (K+) on WUE in two coffee arabica varieties: cv. Castillo and cv. Caturra. Castillo has resistance against coffee leaf rust (CLR) (Hemileia vastatrix Verkeley and Brome), while Caturra is not CLR-resistant. WUE was influenced by yield changes during the years by climate variability due to El Niño–ENSO conditions and CLR incidence. Application of Ca+2 and K+ improved the WUE under such variable conditions. The highest WUE values were obtained with an application of 100 kg CaO ha−1 year−1 and between 180 to 230 kg K2O ha−1 year−1. The results indicate that adequate nutrition with Ca+2 and K+ can improve WUE in the long-term, even underwater deficit conditions and after the substantial incidence. Hence, an optimum application of Ca+2 and K+ in rain-fed coffee plantations can be regarded as an effective strategy to adapt to climate variability and climate change.

Studies were conducted with ozone gas fumigation under vacuum as a methyl bromide alternative against life stages of coffee berry borer (CBB) Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae), and the urediniospores of coffee leaf rust (CLR), Hemileia vastatrix Berkeley & Broome (Basidiomycota: Pucciniales) in green coffee, Coffea spp. L. Fumigation with 10,000 ppm O3 gas under −25.4 mm Hg vacuum1 at 13.0 ± 3.0°C for 6.0 h killed all CBB larvae, pupae, and adults, but did not kill all CBB eggs (~15% survival). Mortality of CLR urediniospores was 100% within the first hour of the 6-h fumigation. Ozone fumigation had no adverse effects on coffee quality. Results indicated that CBB adult hitchhikers may be the only target life stage of quarantine concern, and additional studies focused on this stage. CBB adult survival and reproduction decreased significantly at moisture contents ≤20%, and F1 generation survival did not occur in green coffee at moisture contents ≤15%. As the international standard for green coffee moisture content is 9–12%, adult CBB should not survive or reproduce in exported dry green coffee. Standard industry processing of harvested coffee cherries to the green coffee stage using either mechanical- or sun-drying eliminated CBB infestations from the field. A systems approach is recommended for exporting green coffee to control CBB and CLR that includes eliminating CBB life stages with standard processing methods, reducing moisture content to 9–12% to prevent egg deposition, survival or reproduction, and O3 fumigation to ensure quarantine security against potential CBB adult hitchhikers.

Coffea arabica is the most economically important coffee species worldwide. However, its production is severely limited by diseases such as rust. The mechanisms underlying constitutive defense responses in coffee are still poorly understood, compared with induced defense mechanisms. We aimed to characterize constitutive defense responses of thirteen cultivars of C. arabica. Cultivars were classified under field conditions according to the level of resistance to rust: resistant (R), moderately resistant (MR), and susceptible (S). Based on this classification, the stability of eight reference genes (RGs) was evaluated. The most stable RGs were EF1α, APT1, and 24S. We also evaluated the expression of CaWRKY1, CaPAL1, CaCAD1, and CaPOX1, and activities of PAL, CAD, and POX, which are involved in lignin biosynthesis, and leaf content of total phenolic compounds and lignin. Gene expression and enzymatic activity were not correlated with defense metabolites in the R cultivar group but showed a negative correlation with phenolic compounds in MR cultivars. Cultivar S showed positive correlations of gene expression and enzyme activity with phenolic compounds. These results may assist coffee breeding programs regarding selection of genotypes and in optimization of rust resistance.

espanolEl control biologico aprovecha la capacidad de algunos microorganismos para controlar las poblacionesde vectores en plantas; y poco se conoce de los mecanismos de control con antagonistas contra agentesfungicos. El cafe tiene importancia en el sector agricola con prestigio a nivel mundial. Existen facto resbioticos que delimitan y disminuyen la calidad de la produccion del grano de cafe, destaca la presen-cia de enfermedades causadas principalmente por hongos como Hemileia vastatrixBerkeley & Bromme,causante de la roya anaranjada del cafe, Cercospora coffeicolaBerkeley & Curtis que causa la manchade hierro y Mycena citricolorBerkeley & Curtis, de ojo de gallo. La presente revision tiene por objetivorecopilar informacion bibliografica disponible, respecto al control biologico como alternativa para laagricultura moderna, las interacciones y mecanismos antagonicos a patogenos entre microorganismos,con enfasis en el control biologico de enfermedades causadas por hongos fitopatogenos en el cultivode cafe (Coffea arabicaL.). Las citas bibliograficas muestran que es necesario realizar investigacionesenfocadas en el aislamiento, identificacion y seleccion de microorganismos entre las comunidades mi-crobianas, con enfasis en el discernimiento de los mecanismos que influyen en el ciclo de vida de los pa-togenos y, definir con ello la posible aplicacion biotecnologica durante la produccion de cafe EnglishBiological control takes advantage of the ability of some microorganisms to control populations of vec-tors in plants; however, little is known about the mechanisms of control with antagonists against fun-gal agents. Coffee is important in agricultural sector at a global level. There are some biotic factors which imit and reduce quality in the production of coffee bean, specially is relevant the presence of diseasescaused mainly by fungi such as Hemileia vastatrix Berkeley & Bromme causing orange coffee rust, Cer-cospora coffeicolaBerkeley & Curtis which causes brown eye spot and Mycena citricolorBerkeley & Cur-tis, causing American leaf spot disease. The present review compiles available information related tobiological control in modern agriculture, interactions and antagonist mechanisms to pathogens betweenmicroorganism emphasizing in biological control of diseases caused by phytopathogenic fungi in cof-fee (Coffea arabicaL.). In this sense, research focused in isolation, identification and selection of mi-croorganisms from microbial communities is needed, highlighting the description of mechanismswhich influence the life cycle of pathogens in order to define the possible biotechnological applicationduring the coffee production

Genomic selection (GS) emphasizes the simultaneous prediction of the genetic effects of thousands of scattered markers over the genome. Several statistical methodologies have been used in GS for the prediction of genetic merit. In general, such methodologies require certain assumptions about the data, such as the normality of the distribution of phenotypic values. To circumvent the non-normality of phenotypic values, the literature suggests the use of Bayesian Generalized Linear Regression (GBLASSO). Another alternative is the models based on machine learning, represented by methodologies such as Artificial Neural Networks (ANN), Decision Trees (DT) and related possible refinements such as Bagging, Random Forest and Boosting. This study aimed to use DT and its refinements for predicting resistance to orange rust in Arabica coffee. Additionally, DT and its refinements were used to identify the importance of markers related to the characteristic of interest. The results were compared with those from GBLASSO and ANN. Data on coffee rust resistance of 245 Arabica coffee plants genotyped for 137 markers were used. The DT refinements presented equal or inferior values of Apparent Error Rate compared to those obtained by DT, GBLASSO, and ANN. Moreover, DT refinements were able to identify important markers for the characteristic of interest. Out of 14 of the most important markers analyzed in each methodology, 9.3 markers on average were in regions of quantitative trait loci (QTLs) related to resistance to disease listed in the literature. Made available in DSpace on 2020-10-16T09:14:16Z (GMT). No. of bitstreams: 1 Sousa-et-al-2020.pdf: 564113 bytes, checksum: 4574b3c97e267472a1844b5733671891 (MD5) Previous issue date: 2021

The biotrophic fungus Hemileia vastatrix causes coffee leaf rust (CLR), one of the most devastating diseases in Coffea arabica . Coffee, like other plants, has developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs) have been identified in certain plants as candidates for resistance ( R ) genes or membrane receptors that activate the R genes. The RGAs identified in different plants possess conserved domains that play specific roles in the fight against pathogens. Despite the importance of RGAs, in coffee plants these genes and other molecular mechanisms of disease resistance are still unknown. This study aimed to sequence and characterize candidate genes from coffee plants with the potential for involvement in resistance to H. vastatrix . Sequencing was performed based on a library of bacterial artificial chromosomes (BAC) of the coffee clone ?Híbrido de Timor? (HdT) CIFC 832/2 and screened using a functional marker. Two RGAs, HdT_LRR_RLK1 and HdT_LRR_RLK2, containing the motif of leucine-rich repeat-like kinase (LRR-RLK) were identified. Based on the presence or absence of the HdT_LRR_RLK2 RGA in a number of differential coffee clones containing different combinations of the rust resistance gene, these RGAs did not correspond to any resistance gene already characterized (SH1-9). These genes were also analyzed using qPCR and demonstrated a major expression peak at 24 h after inoculation in both the compatible and incompatible interactions between coffee and H. vastatrix . These results are valuable information for breeding programs aimed at developing CLR-resistant cultivars, in addition to enabling a better understanding of the interactions between coffee and H. vastatrix. Made available in DSpace on 2022-01-26T14:00:41Z (GMT). No. of bitstreams: 1 receptor-like-kinase.pdf: 797260 bytes, checksum: 18841c8c3f9b08408ff2d898ecc48880 (MD5) Previous issue date: 2021

International audience; 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 social-ecological shocks.

Information obtained from studies of spatial variability and the Diagnosis and Recommendation Integrated System (DRIS) may contribute to understanding better the relationship between mineral nutrient balance and factors that limit the crop yield. This study shows that nutritionally balanced plants may be associated with low productivity in Conilon coffee fields. The study was carried out on a highly productive Conilon coffee (Coffea canephora) field, in São Mateus, state of Espírito Santo, Brazil. A sample grid was established with 100 points, each point linked to one plant. Twenty pairs of leaves from each plant were collected from productive branches to create a sample for nutritional analysis. The rust incidence (Hemileia vastatrix), the presence of the coffee borer (Hypothenemus hampei), and the physical characteristics of the soil were evaluated in each sampled plant. DRIS and Nutrient Balance Index (NBI) were calculated, and from the yield data, they were characterized using descriptive statistics. Maps were created showing the spatial distribution of the NBI, yield, total sand, and incidence of rust and coffee borer. It was verified the low relationship between nutritional balance and yield in Conilon coffee, suggesting that non-nutritional factors also influenced plant production. In areas of the maps with high NBI, the plant’s nutritional balance was the main limiting factor of production, since most plants in this area produced less than the average productivity of the plants sampled. The use of a geostatistics tool combined with the NBI resulted in better understanding of the relationship between nutritional and non-nutritional variables on the Conilon coffee yield. RESUMO Informações obtidas a partir de estudos de variabilidade espacial e do Sistema Integrado de Diagnose e Recomendação (DRIS) poderão contribuir para o melhor entendimento da relação entre o balanço de nutrientes e os fatores que limitam a produtividade das culturas. Este estudo mostra que plantas equilibradas nutricionalmente podem estar associadas à baixa produtividade em café Conilon (Coffea canephora). O estudo foi realizado em uma lavoura altamente produtiva de café Conilon em São Mateus, ES. Foi estabelecida uma grade amostral com 100 pontos, cada ponto relacionado a uma planta. Vinte pares de folhas de cada planta foram coletados de ramos produtivos compondo uma amostra para análise nutricional. A incidência da ferrugem (Hemileia vastatrix), a presença da broca do café (Hypothenemus hampei), e características físicas do solo também foram coletadas para cada planta amostrada. O DRIS e o Índice de Equilíbrio dos Nutrientes (IEN) foram calculados e, com os dados de produtividade, foram caracterizados utilizando estatística descritiva. Foram criados mapas com a distribuição espacial do IEN, produtividade, areia total e incidência de ferrugem e da broca do cafeeiro. Verificou-se baixa relação entre equilíbrio nutricional e produção no café Conilon, sugerindo que fatores não nutricionais também influenciaram na produtividade das plantas. Nas áreas dos mapas com alto IEN, o balanço nutricional da planta foi o principal fator limitante da produção, pois a maioria das plantas nessa área produziu menos que a produtividade média das plantas amostradas. O uso de uma ferramenta geoestatística combinada com o IEN resultou em melhor compreensão da relação entre variáveis nutricionais e não nutricionais sobre a produtividade de café Conilon.

Landscape structure influences the spread of plant pathogens, primarily by affecting pathogen dispersal. Coffee leaf rust (Hemileia vastatrix), a fungal disease that causes heavy economic losses in the coffee industry, is likely to be affected by landscape structure via dispersal of its wind-borne spores. Previous studies have found positive associations between leaf rust incidence and the proportion of pasture cover, suggesting that deforestation may facilitate rust spore dispersal. We explored this idea by modeling the spread of rust transmission in simulated landscapes. Specifically, we modeled within-patch transmission using a probabilistic cellular automata model, and between-patch transmission using a random walk with spore movement inhibited by forest canopy cover. We used this model to understand how the spread of coffee rust is affected by: 1) clustering of coffee plants, 2) clustering of deforestation, and 3) proportion of landscape deforestation. We found that clustering of coffee plants is the primary driver of rust transmission, affecting the likelihood and severity of rust outbreak. Deforestation is important in landscapes with high clustering of coffee: rust outbreaks are more severe in landscapes with a higher proportion of deforested areas, and more variable in landscapes where deforested areas are more evenly dispersed throughout the landscape.

Background The occurrence of diseases can alter coffee (Coffea arabica L.) metabolism, causing changes in the composition of coffee beans and beverage quality. However, little is known about which aspects of coffee quality are actually altered by rust (Hemileia vastatrix Berk et Br.) and by its main control methods. The effect of chemical and genetic methods for the control of coffee rust on the quality of coffee beans and beverage was investigated. Results Both genetic and chemical control reduce the damage caused by the disease in the composition of coffee beans. Genotypes with resistant ancestry, even with resistance breakdown, respond better to chemical control. The combination of genetic and chemical control favors an increase in the sugar content in the beans. Conclusions Despite the fact that both genetic and chemical control are effective in reducing disease damage regarding the chemical composition of beans, the quality potential of Timor Hybrid genotypes associated with the cancellation of rust expression through the joint action of genetic and chemical control favors the composition of beans and, consequently, the quantitative assessment of sensory attributes, adding value to the final product. © 2020 Society of Chemical Industry.

Introduction.Coffee (Coffea arabicaL.) is an important crop in producing countries like Peru, where approximately two million families depend on its production, distribution, and marketing. But in recent years, climate change has increased the presence of coffee leaf rust - CLR (H. vastatrix), a disease that has decreased Peruvian production by up to 27%.Objective.Monitor the severity of CLR in different genotypes of coffee cv. Typica from April-2017 to March-2018.Material and methods.The experiment was carried out in the coffee germplasm bank at the Development Regional Institute (IRD)-Selva of the Universidad Nacional Agraria La Molina. The severity and the area under the disease progress curve (AUDPC) in the lower, middle, and upper part of coffee trees were quantified.Result.There was high severity and AUDPC in the dry season (low precipitation) compared to the rainy season (high precipitation). Severity and AUDPC gradually decreased from the bottom to the top of the plant (lower>middle>upper). Also, UNACAF-24A, UNACAF-16, UNACAF-158, and UNACAF-162 genotypes stood out by showing lowest severity (0-1.1 %) and AUDPC (0-714) in the experiment.Conclusion.In this experiment, the genotypes in dry season presented high peaks of severity and UDPC of CLR, meanwhile, in rainy season the presence of CLR was lower. However, in both seasons, severity and AUDPC gradually decreased from the lower third to the upper thirf of the plant. Finally, UNACAF-24A, UNACAF-16, UNACAF-158, and UNACAF-162 presented the lowest degrees of severity of CLR. Introducción.El café es un cultivo importante en los países productores como el Perú, donde aproximadamente dos millones de familias dependen de su producción, distribución y comercialización. En los últimos años, el cambio climático ha aumentado la presencia de la roya del café (H. vastatrix), una enfermedad que ha disminuido hasta en un 27 % la producción peruana.Objetivo.Monitorear la severidad de la roya del café en diferentes accesiones de café cv. Typica, desde abril 2017 hasta marzo 2018.Materiales y métodos.El experimento se llevó a cabo en el banco de germoplasma de café en el Instituto Regional de Desarrollo (IRD)-Selva de la Universidad Nacional Agraria La Molina. Se cuantificó la severidad y el área bajo la curva del progreso de la enfermedad (ABCPE) en la parte baja, media y alta de las plantas de café.Resultados.Hubo alta severidad y ABCPE en la estación seca en comparación con la estación húmeda. La severidad y el ABCPE disminuyeron gradualmente desde la parte baja hacia la parte alta de la planta (parte baja>media>alta). Las accesiones UNACAF-24A, UNACAF-16, UNACAF-158 y UNACAF-162 tuvieron la menor severidad (0-1,1 %) y ABCPE (0-714) en el experimento.Conclusión.En este experimento, en la estación seca (estación con poca precipitación) los genotipos presentaron altos picos de severidad y ABCPE de roya, mientras que en la estación lluviosa la presencia de la roya del café fue menor. Sin embargo, en ambas estaciones, la severidad y ABCPE disminuyeron gradualmente desde el tercio inferior hasta el tercio superior de la planta. Finalmente, UNACAF-24A, UNACAF-16, UNACAF-158 y UNACAF-162, presentaron los menores grados de severidad y de ABCPE.

La roya del cafeto (Hemileia vastatrix) es una enfermedad devastadora para los cafetales en México. Los métodos de control se han centrado en el uso de fungicidas, pero sin éxito, por lo que el control biológico representa una alternativa. Las larvas de Mycodiplosis se reportan como depredadoras de H. vastatrix, pero la información disponible sobre este insecto es limitada. Los objetivos de esta investigación fueron describir el tipo de relación entre H. vastatrix y Mycodiplosis y conocer su patrón de distribución en el dosel de la planta. Se eligieron tres plantaciones con incidencia de roya en Xochitlán de Vicente Suárez, Puebla y se registraron periódicamente la severidad de la roya y el número de larvas de Mycodiplosis por estrato de la planta. Se seleccionaron 25 plantas por parcela, muestreada en cinco de oros. Las larvas se identificaron molecularmente. Mediante la prueba de Kruskal Wallis, se encontraron diferencias significativas entre sitios de muestreo en la severidad de roya y el número de larvas de Mycodiplosis, detectando una correlación positiva entre la severidad de la roya y el número de larvas de Mycodiplosis. La distribución de Mycodiplosis fue similar en los estratos (baja, media y alta) de las plantas evaluadas.

Coffee rust (Hemileia vastatrix Berkeley & Broome) is the main coffee disease in Brazil. Coffee rust control is calendar-based and performed by applying chemicals in order to avoid the outburst of disease epidemics. The aim of this work was to identify coffee rust using multispectral orbital sensing through analyses utilising vegetation indices and coffee rust incidence, defoliation and yield data obtained in situ. Field samples were georeferenced using a high-accuracy global navigation satellite system receiver in two plots, in a 42-year-old, leaf rust susceptible coffee cultivar. Conventional chemical control of rust was performed in only one of the plots to serve as control. Coffee rust incidence in areas with and without chemical control was assessed over 5 months, from December 2018 to April 2019, a period with optimal environmental conditions for disease occurrence. Following analyses of different vegetation indices and data sampled in the coffee crop, Pearson’s correlations between the variables were verified. Reported correlations occurred mainly among coffee rust incidence levels in February 2019 and vegetation indices calculated using Sentinel-2 images from August 2018, September 2018 and February 2019 [IRECI r = 0.566; IRECI r = 0.493; NDMI r = − 0.518; NDVI(RE1) r = − 0.562; CI(RE1) r = − 0.573; MSR(RE1) r = − 0.569], in areas without coffee rust control. Indices based on relationships between bands in the Red-Edge and Near Infra-Red regions were more sensitive to spectral changes in vegetation due to variation in coffee rust occurrence over time.

From 2013 to 2015, a study was conducted on 29 coffee plots to assess the influence of landscape context and plot features on the epidemics of coffee leaf rust (CLR) descriptors in Gumay and Setema districts, Southwest Ethiopia. Maximum CLR severity and number of sporulating lesion density per leaf was significantly correlated with different land use types (tree density at 100 m, 200 m, pasture and crop lands at 200 m circular radius), and plot features (altitude, North-South aspect, East-West aspect and leaf area index) over different years of observation. High tree density in the surrounding coffee plots significantly increased the severity of the disease. There was a general decreasing trend of CLR severity, sporulating lesion density and proportion of leaf fall over the altitudinal gradient. The interaction of landscape context with CLR descriptors found were so complex and need further detail analysis.

Occurrence and intensity coffee leaf rust (Hemileia vastatrix) depend mainly on the irrigation system, soil fertility and plant nutrition. The aim of this study was to evaluate the spatial distribution of coffee leaf rust relative to soil fertility and plant nutrition in coffee plantations irrigated by drip and center pivot using geostatistics. The experiment was installed in two experimental areas, with a drip and center pivot irrigation system of 11 and 17 ha and 52 and 50 georeferenced sampling points, respectively. The incidence of the disease, soil fertility and plant nutritional status were evaluated at each point. For the drip system, there was no significant correlation between disease incidence and leaf contents of N, P, K, and Ca. Regarding fertility, there was a positive correlation only for P and the disease incidence. For the center pivot system, there was a positive correlation between coffee leaf rust and Ca, P, and K, and negative for P and K in the leaves, varying according to the assessment date. In soil, only Ca correlated negatively whereas K positively correlated with incidence. The spatial distribution of the disease and nutrients varied over the years, being observed a gradient from foci in the kriging maps elaborated after the adjustment of the exponential model.

Coffee leaf rust is a polycyclic disease that causes severe epidemics impacting yield over several years. For this reason, since the 1960s, more than 20 models have been developed to predict different indicators of the disease's development and help manage it. In existing models, standardized periods of influence of the meteorological predictors of the disease are determined a priori, based on strong assumptions. However, the appearance of a symptom or sign can be influenced by complex combinations of meteorological variables acting at different times and for different durations. In our study, we monitored a total of 5400 coffee leaves during a year and a half, in different agroforestry systems, in order to detect the onset dates of the disease symptoms, such as lesion emergence, and signs, such as sporulation and infectious area increase. In these agroforestry systems, we also recorded microclimate. We statistically identified the complex combinations of microclimatic variables responsible for changes in lesion status to construct three models predicting lesion emergence probability, lesion sporulation probability and growth of its infectious area. Our method allowed the identification of different microclimatic variables that fit well with the knowledge about the coffee leaf rust biology. Minimum air temperature from 20 to 18 days before a lesion emergence explained the status change from healthy to emergence of visible lesion, possibly because the short germination phase is stimulated by low temperatures. We also found a unimodal effect of rainfall over a period of 10 days, 33 days before lesion emergence, with a maximum at 10 mm. Below this threshold, uredospore dispersal is efficient, increasing the lesion appearance probability; above this threshold, wash-off effects on uredospores probably occurs, decreasing the probability of lesion emergence. In addition, we identified microclimatic variables whose influence on coffee leaf rust had not been described before. These variables are likely to be involved in the internal development phases of the disease in the coffee leaves: (1) unimodal effects of maximum air temperature in different periods on sporulation and infectious area growth (2) positive and unimodal effects of rainfall in different periods on sporulation and (3) a negative effect of leaf thermal amplitude in different periods on lesion emergence, sporulation and infectious area growth. Although these models do not provide predictors of the level of disease attack, such as incidence, they provide valuable information for warning systems and for mechanistic model development. These models could also be used to forecast risks of infection, sporulation and infectious area growth and help optimize treatment recommendations.

International audience; Coffee industry is threatened by production losses due to the rust disease since 1850. The coffee leaf rust (CLR) disease has an important social and economical impacts and its control is still a challenge. The CLR pathogen is the fungus Hemileia vastatrix Berkeley & Broome (Basidiomycota, order Pucciniales) that is currently controlled by using non-specific anti-fungal chemicals spraying. The advances in molecular biology and bioinformatics may allow the identification of new targets and environmentally safe strategies for controlling CLR. Several genomic and transcriptomic data are available for H. vastatrix that allow searching for new proteins to achieve a better disease control. We used the dataset of 34,242 sequences from the fungal genome and transcriptome, with a filtering strategy for protein annotation, structure and cell sublocalization to select three essential proteins related to steroid synthesis, cell membrane, and cell wall metabolism. This short paper reports the ongoing study to allow the development of new molecules that might be validated and contribute to new products that are specific and ecologically friendly.