Control Of Coffee Leaf Rust Research Articles

First Description of Simplicillium lanosoniveum, a Potential Antagonist of the Coffee Leaf Rust from Cuba

(1) The fungal genus Simplicillium (Cordycipitaceae: Hypocreales) has an extensive distribution and a broad spectrum of hosts and substrates. The species Simplicillium lanosoniveum is a mycoparasite with potential for biological control of coffee leaf rust, Hemileia vastatrix. Morphologically, Simplicillium closely resembles mycoparasitic and entomopathogenic Lecanicillium fungi, often resulting in misidentification. A fungal isolate was obtained from leaf-rust-infested coffee plants from Cienfuegos Province, Cuba. (2) Combined analyses of morphology and molecular markers (ITS, LSU, EF-1alpha) were used for fungal identification. (3) In the NJ, ML, and BI phylogenies which were reconstructed, the isolate LBSim-01 was located in the Simplicillium lanosoniveum clade. This species-level identification was supported by morphological features. (4) The isolate LBSim-01 was assigned to the species Simplicillium lanosoniveum. This is the first description of a Simplicillium fungus associated with coffee leaf rust in Cuba. The presented results hold implications for the biological control of this economically relevant plant disease.

Coffee Leaf Rust: Wreaking Havoc in Coffee Production Areas Across the Tropics

Abstract Coffee ( Coffea spp.) originates from the tropical montane rainforest understorey. In this shaded environment, the coffee plant has co-evolved with a wide array of pests and diseases. The fungal pathogen Hemileia vastatrix is the most notorious of all known coffee plant diseases. With a rich history rooted in colonial trade and power struggles, H. vastatrix has had its lion’s share of research and scrutiny by the plant pathology community. Though this disease was discovered more than 150 years ago, many unknowns concerning its spread and persistence across the tropics still exist today. Despite its relevance to coffee production, there is little global data that synthesizes the impact of this disease on coffee yield and plant health. Best practices for control of coffee leaf rust are contentious. Genetic resistance has been breaking down in cultivars across the coffee belt over the past decade. How can farmers best control outbreaks of the disease? Are these practices at odds with new trends and challenges in coffee farming (e.g. organic, biodiversity-friendly, agroforestry etc.). What are the future prospects of our global coffee supply under pressure from this rampant disease? All these questions are examined in this case study using pertinent literature sources and supplemented by coffee farmers or extension service providers in Latin America and Africa. Information © The Author 2023 Cover photo courtesy of the author.

Influence of arbuscular mycorrhizal fungi on biological control of coffee leaf rust (Hemileia vastatrix BERK. & BROOME)

Inoculating plants with arbuscular mycorrhizal fungi (AMF) protects host plants against biotic stressors such as diseases. Therefore, the objective of this study was to evaluate the influence of arbuscular mycorrhizal fungi in the biological control of coffee leaf rust (CLR) infections. The research involved two varieties of coffee (Caturra and Pache) and three inocula of AMF: Moyobamba (Acaulospora mellea, Acaulospora sp.1, Glomus geosporum, Glomus sp.1, and Glomus sp.2), El Dorado (Acaulospora rugosa, Acaulospora spinosissima, Acaulospora lacunosa, Glomus sinuosum and Ambispora appendicula) and Huallaga (Acaulospora mellea, Acaulospora sp.1, Acaulospora sp.2, Glomus macrocarpum and Glomus sp.2), in addition to a control treatment without application of AMF (non-AMF). Inoculation of vegetatively propagated coffee plants with AMF was observed to induce tolerance to CLR. The incidence of CLR in non-AMF coffee plants was 43.7 %, while in the coffee plants subjected to the inocula Moyobamba, El Dorado and Huallaga, the incidences were 22.1, 22.7 and 13.2 %, respectively. Likewise, the severity in non-AMF coffee plants was 34.8 %, while in the coffee plants subjected to the three kinds of inocula, the severities were 21.1, 20.4 and 12.0 %, respectively. Thus, mycorrhizal inoculation of coffee plants at the nursery stage reduces the negative effect of CLR infection after the plants are taken to field conditions, representing a sustainable option for their biological control.

An Overview of the Mechanisms Involved in Coffee-Hemileia vastatrix Interactions: Plant and Pathogen Perspectives

Coffee is one of the most consumed beverages in the world. It is also one of the most globally traded commodities. Coffee leaf rust (CLR), caused by the biotrophic fungus Hemileia vastatrix, is the most important disease affecting Arabica coffee growing worldwide, leading to significant yield losses if no control measures are applied. A deep understanding of the complex mechanisms involved in coffee-H. vastatrix interactions, such as the pathogen variability and the mechanisms governing plant resistance and susceptibility, is required to breed efficiently for durable resistance and design new approaches for crop protection. Here we summarize our current understanding across multiple areas related to pathogen infection, variability and candidate effectors, breeding for disease resistance, and the various components of the coffee immune system, by reviewing a comprehensive body of research on CLR and the advances recently made. We also update information about the defense responses activated by the application of plant resistance inducers, a promising alternative to fungicides in the control of CLR. Moreover, we identify and discuss future directions for further research.

Potential of the Dithiocarbimate Fungicides on the Control of Coffee Leaf Rust and Asian Soybean Rust

Coffee leaf rust (Hemileia vastatrix) and Asian soybean rust (Phakopsora pachyrhizi) are diseases that cause great losses in the productivity of these crops, not only in Brazil but on a global scale. Coffee and soybean varieties grown are susceptible to these diseases. Thus, it is necessary to search for efficient compounds for their chemical control, mainly from the group of protectors or residuals so that they can be formulated with systemic fungicides to control the diseases. This allows not only the efficient management of diseases but also the prevention of the emergence of resistant mutants in the populations of these pathogens. In this context, the present study aimed to evaluate the sensitivity and effect of bis(N-R-sulfonyldithiocarbimato)zincate(II) salts fungicides on the epidemiological components of pathosystems coffee × H. vastatrix and soybean × P. pachyrhizi. Initially, four zinc(II) complexes salts (1A, 2A, 1B, and 2B) with N-R-sulfonyldithiocarbimates were synthesized. In the first experiment, the in vitro sensitivity of H. vastatrix and P. pachyrhizi was studied for the four compounds synthesized and mancozeb at 0.5, 5.0, 50.0, 100.0 and 200.0 µmol L-1. All the compounds synthetized in this study had inhibitory effects on H. vastatrix and P. pachyrhizi. In the greenhouse it was studied the effect of bis(N-R-sulfonyldithiocarbimato)zincate(II) salts on the epidemiological components of coffee leaf rust and Asian soybean rust. For the pathosystem coffee × H. vastatrix, there were no differences in the values obtained for the bis(N-R-sulfonyldithiocarbimato)zincate(II) salts and mancozeb for the latent period. For the sporulated lesion variable, the control treatment had a mean value of 149.0 lesions/leaf, differing significantly from the other treatments. The mean value of compound 2B was estimated as 25.0 lesions/leaf, differing significantly from treatments 1A, 1B, 2B, and mancozeb. Treatments 1A, 1B, 2B, and mancozeb did not differ significantly from each other. For the Asian soybean rust, the area under the disease progress curve had a mean value of 75.8 for the control, while for the 2A treatment the value was 4.1, differing from the other compounds. The treatments 1A, 1B, 2A, and mancozeb did not differ significantly from each other. In conclusion, compounds 1A, 2A, and 1B were more efficient in the control of the coffee leaf rust, while compound 2A was efficient in the control of the Asian soybean rust.

A fungus-eat-fungus world: Digitopodium, with particular reference to mycoparasites of the coffee leaf rust, Hemileia vastatrix

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.

Factors influencing the performance of phosphites on the control of coffee leaf rust

ABSTRACT This study investigated the effect of different phosphites on the control of coffee leaf rust (CLR) caused by Hemileia vastatrix, considered the major disease affecting coffee yield worldwide. Three-month-old coffee plants were sprayed with two doses each of the phosphite solutions (standar., and double), as follows: K (40% P2O5; 1.., and 3 mL∙L-1), K (30% P2O5; ., and 6 mL∙L-1), Cu (2.., and 5 mL∙L-1), Mn+Zn (., and 6 mL∙L-1., and Na (., and 6 mL∙L-1) 24 h before being inoculated with H. vastatrix. Leaves were not washed or washed with deionized water after the foliar phosphites spray. Plants sprayed with water served as the control treatment. Inoculation was performed on the abaxial side of the first pair of expanded leaves using a camel hairbrush with a suspension of urediniospores (1 mg per leaf). All phosphites applied at the standard doses (from 1.5 to 3 mL∙L-1) reduced the total number of pustules (TNP) per leaf by 28-69% regardless of washing treatment. The biggest reductions were observed for Cu phosphite, which decreased the TNP per leaf by 6., and 69% withou., and with leaf washing, respectively. A similar trend was observed when the double doses of phosphites (from 3 to 6 mL∙L-1) were used, though Na phosphite without leaf washin., and Mn/Zn phosphite withou., and with leaf washing were not efficient to reduce the TNP per leaf. Without leaf washing, only C., and Na phosphites decreased CLR severity at the standard doses (53-61%), whereas all phosphites, except the Mn/Zn phosphite, reduced CLR severity at the double dose. The CLR severity was decreased using K 30%, K 40., and Cu phosphites when applied at the standard doses with leaf washing (41-59%). With double doses, only C., and Na phosphites decreased CLR severity by 55% for both treatments. In conclusion, the efficiency of the phosphites for CLR control varied according to the accompanying cation, dos., and washing conditions. The Cu phosphite resulted in the best CLR control regardless of the dose use., and the washing conditions.

Performance of a weather-based forecast system for chemical control of coffee leaf rust

Coffee leaf rust (CLR), caused by Hemileia vastatrix, is a major disease in coffee fields worldwide. In Brazil, fungicides are extensively used for disease control; nevertheless, disease outbreaks can occur if applications are not properly timed. In this study, we evaluated a CLR forecast system (FS) for scheduling fungicide foliar sprays in seven field trials (conducted in five different sites). Two trials were carried out in 2015–16 season and five in the 2016–17 season. The CLR-FS uses the cumulative infection rate based on daily infection rates, accumulated since the beginning of each season, considering minimum air temperature and average relative humidity. The treatments were based on soil drench followed by foliar sprays: T1 - control; T2 - two or three sprays according to the regional calendar of each site; T3 - FS with more conservative thresholds (MC) with three sprays; T4 - FS with less conservative thresholds (LC) with three sprays; T5 - FS LC with two sprays; T6 - same as T3, without soil drench. We assessed CLR incidence monthly and estimated the area under the disease progress curve (AUDPC) for comparison of treatments. In six experiments, the sprays adjusted by the FS showed lower AUDPC than T2. However, all treatments controlled CLR appropriately in seven experiments. In four experiments, treatment T5, with only two foliar sprays, was as efficient as the other treatments with three applications. The CLR-FS used in a less conservative threshold could improve chemical control of CLR; however, regional calibrations may be necessary.

Primary Metabolism Is Distinctly Modulated by Plant Resistance Inducers in Coffea arabica Leaves Infected by Hemileia vastatrix.

Epidemics of coffee leaf rust (CLR) leads to great yield losses and huge depreciation of coffee marketing values, if no control measures are applied. Societal expectations of a more sustainable coffee production are increasingly imposing the replacement of fungicide treatments by alternative solutions. A protection strategy is to take advantage of the plant immune system by eliciting constitutive defenses. Based on such concept, plant resistance inducers (PRIs) have been developed. The Greenforce CuCa formulation, similarly to acibenzolar-S-methyl (ASM), shows promising results in the control of CLR (Hemileia vastatrix) in Coffea arabica cv. Mundo Novo. The molecular mechanisms of PRIs action are poorly understood. In order to contribute to its elucidation a proteomic, physiological (leaf gas-exchange) and biochemical (enzymatic) analyses were performed. Coffee leaves treated with Greenforce CuCa and ASM and inoculation with H. vastatrix were considered. Proteomics revealed that both PRIs lead to metabolic adjustments but, inducing distinct proteins. These proteins were related with photosynthesis, protein metabolism and stress responses. Greenforce CuCa increased photosynthesis and stomatal conductance, while ASM caused a decrease in these parameters. It was further observed that Greenforce CuCa reinforces the redox homeostasis of the leaf, while ASM seems to affect preferentially the secondary metabolism and the stress-related proteins. So, the PRIs prepare the plant to resist CLR but, inducing different defense mechanisms upon pathogen infection. The existence of a link between the primary metabolism and defense responses was evidenced. The identification of components of the plant primary metabolism, essential for plant growth and development that, simultaneously, participate in the plant defense responses can open new perspectives for plant breeding programs.

Tank mix application of copper hydroxide either with cyproconazole or pyraclostrobin fungicides reduced the control of coffee leaf rust

Coffee leaf rust (CLR) is a major disease that occurs in all coffee-growing regions, and chemical control is the most effective strategy to control the disease. Usually, this control is based on the application of contact and/or systemic fungicides to the foliage of the plants, and a very common practice is the use of tank-mix solution of fungicides to reduce the costs of the application. The aim of this study was to evaluate the efficacy of mixtures of systemic fungicides (triazoles and strobilurins) and copper hydroxide on the germination of uredospores of Hemileia vastatrix and on the control of CLR. The results showed that the effectiveness of a fungicide can be affected when used in mixtures with another fungicide, resulting in ineffective disease control. When copper hydroxide was combined with cyproconazole, the inhibition of uredospore germination was lower than when copper hydroxide was used alone. For both fungicides pyraclostrobin and cyproconazole, effectiveness in the control of CLR was reduced with the presence of copper hydroxide in the mixture, and this loss in efficacy may be associated with the occurrence of alkaline hydrolysis of the fungicides when they are mixed with copper hydroxide. The findings of this study demonstrate that tank mix application of copper hydroxide either with cyproconazole or pyraclostrobin fungicides reduces the control of CLR, so this practice should be avoided by growers.

Drying Time of Systemic and Protectant Fungicides on Coffee Leaves Exposed to Artificial Rain for the Control of Leaf Rust

The drying time of pesticides on the leaves and the resistance of the deposits to rain removal are essential for success in controlling plant diseases. Because the fungicide application is performed during the rainy season, it is crucial to study the resistance of chemical deposits on the leaf surface for the control of the coffee leaf rust caused by Hemileia vastatrix. Thus, the present work analyzed the effect of an simulated rain (30 min), after several drying time of the deposits, on the removal of (i) copper oxychloride alone and associated to mineral and the adjuvant polyoxyethylene alkylphenol ether and also (ii) before several drying time, on the removal of the epoxiconazol + pyraclostrobin formulation mixed with copper hydroxide and micronutrients applied on coffee leaves, for the control of leaf rust. Around 85% and 45% of the treatments had copper retention > 30% after 120 min and 480 min, respectively, of drying time before the rain. At 480 min, retention of copper oxychloride + 0.75% mineral oil was > 30%, whereas copper oxychloride + adjuvant polyoxyethylene alkylphenol ether at 0.05% and 0.1%, respectively was 40% or higher. When copper oxychloride was added to 0.5% mineral oil at 0.05% to 0.20% of adjuvant polyoxyethylene alkylphenol ether at 480 min of drying time, copper retention was > 30%. When copper oxychloride was added to 0.75% mineral oil, copper retention was > 30% at 0.05% and 0.10 % of adjuvant polyoxyethylene alkylphenol ether. Five of the treatments with copper retention > 50% with 120 min of drying time were reduced to only two (copper oxychloride + 0.75% mineral oil; copper oxychloride + (1.0% mineral oil + 0.1% adjuvant polyoxyethylene alkylphenol ether) with copper retention > 30%, at the drying time of 480 min. All the treatments differed from the control but did not differ between each other for the coffee leaf rust control. The percentage of control ranged from 94.6% to 100% and from 71.3% to 99.5% at 180 min and 480 min of drying time, respectively. Copper retention varied from 32.2% to 55.2% and from 23.7% to 51.5%, at 180 min and 480 min of drying time, respectively, for the best treatments. The treatment with the highest copper retention was copper oxychloride + 0.75% mineral oil, both at 180 min and 480 min of drying time. The best treatments for leaf rust control were not always those with the highest copper retention by the leaves. The highest copper retention by the leaf surface was achieved with copper oxychloride mixed with 0.75% mineral oil; this treatment resulted in > 97% of coffee leaf rust control. Adding adjuvant polyoxyethylene alkylphenol ether to the mixture does not necessarily favor the tenacity and efficiency of the copper oxychloride for the coffee leaf rust control. We concluded that the copper oxychloride acts differently for the coffee leaf rust control, depending on the concentration of added mineral oil and adjuvant polyoxyethylene alkylphenol ether time zero. Pyraclostrobin + epoxiconazol alone or mixed with copper hidroxide controlled 100% of the disease after 30 min, 120 min and 480 min of spraying, but when micronutrients was added to pyraclostrobin + epoxiconazol and copper hidroxide control of coffee leaf rust reached 100% at drying time of 120 and 480 min.

Control of Coffee Leaf Rust by Chitosan Oligomers and Propolis

Abstract Broad scale use of chemical pesticides is known to have produced broad scale environmental impact worldwide and, at the same time, discovery and registration of new molecules to be used as insecticides, herbicides and fungicides have slowed significantly along the last decades, reducing the number of options for pest control by the farmers. Searches for novel environmentally friendly products are a recognized priority. In this work, aqueous solutions of chitosan oligomers (COs) and propolis (P), individually or as binary mixtures, were tested against Hemileia vastatrix, the fungus which causes coffee leaf rust, the worst disease of coffee. Germination of H. vastatrix was inhibited up toll 99 % by COs, followed by the mixture of COs-P and P individually (germination inhibition of 96 % and 54 % respectively). Testing those products on detached coffee leaf discs also produced promising results when COs were applied before H. vastatrix inoculation. These results may lead to the discovery of new antifungal products for the control of coffee leaf rust.

Evaluation of Different Botanicals for the Control of Coffee Leaf Rust (Hemileia vastatrix Berkeley and Broome)

Evaluation of Different Botanicals for the Control of Coffee Leaf Rust (Hemileia vastatrix Berkeley and Broome)

DMI and QoI fungicides for the control of coffee leaf rust

This study investigated the ability of different triazole and strobilurin fungicides either alone or combination when applied to the leaves and triazole to the soil for control of Coffee Leaf Rust (CLR). The experiments were performed in a greenhouse using three month-old coffee seedlings, and in the field with five years old plants using the susceptible variety ‘Catuai vermelho’, at elevation of 750 m, from 2010 to 2012, in Vicosa, Minas Gerais State, Brazil. The effects of triazole (triadimenol, cyproconazole and epoxiconazole) and strobilurin (azoxystrobin, trifloxystrobin, pyraclostrobin) was first studied in a greenhouse to evaluate the translaminar effect on CLR control. Based on the results obtained in the greenhouse, a field experiment was performed to evaluate the effect of triazole applied to the soil and triazole + strobilurin sprayed on CLR control and the effect on coffee berry yield of the plants. The different fungicides applied in the greenhouse reduced CLR severity by 8.9 % (trifloxystrobin), 79.4 % (azoxystrobin), 82.0 % (triadimenol), 93.2 % (cyproconazole), 96.6 % (epoxiconazole) and 98.5 % (pyraclostrobin) compared to that in the control plants. In the field experiment triazole + strobilurin fungicides provided effective CLR control. The co-application of epoxiconazole and pyraclostrobin or azoxystrobin sprayed twice resulted in the most effective CLR control and maintained the highest coffee berry yield. The incidence of CLR was 83.5, 54.0 and 78.5 % for the control treatments, whereas the incidence did not exceeded 24.4, 37.0 and 39.0 % on the sprayed plants. The average coffee berry yield increased by 33.9 % (lowest value) when applying triadimenol to the soil in November followed by cyproconazole + trifloxystrobin sprayed in December and February, and increased by 99.1 % (highest value) in the treatment with epoxiconazol + pyraclostrobin sprayed in December and March compared with plants that did not receive any fungicide application. The control treatment and that of triadimenol applied to the soil in November followed by cyproconazole + trifloxystrobin sprayed in December and February yielded less than 1800 (1320 to 1800) kg/ha of processed coffee, whereas the other treatments more than 2100 (2142 to 2676) kg/ha. Treatments with cyproconazole applied to the soil in November followed by cyproconazole + azoxystrobin sprayed on the leaves in December and February, epoxiconazol + pyraclostrobin sprayed on the leaves in December and March, and cyproconazole + azoxystrobin sprayed on leaves in December, February and April yielded more than 2340 (2340 to 2676) kg/ha of processed coffee. This is the first report indicating that a triazole fungicide applied to the soil and triazole + strobilurin fungicide sprayed on the leaves, efficiently controlled CLR and significantly increased coffee berry yield for three seasons.

Monitoring of leaf rust in conilon coffee clones to improve fungicide use

The main management strategy for coffee leaf rust (Hemileia vastatrix) in conilon coffee is based on the application of fungicides using a fixed schedule without considering the epidemiological aspects of the disease. In order to turn chemical control less subjective and more efficient, two systems of coffee leaf rust management were tested: 1) application of systemic fungicide based on the intensity of the disease present in each conilon clone of the “Conilon Vitoria” variety, according to the disease incidence; threshold of 5 % incidence of the disease was adopted to spray the fungicide, and 2) application of systemic fungicide to the soil, followed by foliar application in the beginning of the rainy season. The experiments were performed in two municipalities of the Espirito Santo State, Nova Venecia e Castelo. Monthly evaluations of disease incidence were performed between September 2010 and August 2011. The results showed that chemical control of coffee leaf rust in conilon coffee should be performed differently, for each clone, of the clonal Vitoria variety. The 5 % threshold of the disease incidence was reached at different time of the coffee grower season. The strategy to apply systemic fungicide to the leaves, to control conilon leaf rust, based on the disease incidence of 5 % was more effective than soil application system. Application of systemic fungicide to the soil did not control the disease. In conclusion, monitoring the incidence of coffee leaf rust in all the clones is an important strategy to decide the appropriate time to apply fungicides.

Effect of foliar application of potassium silicate on the progress of coffee leaf rust

In order to evaluate the effect of potassium silicate spray on the control of coffee leaf rust and coffee yield, an experiment was conducted during the 2005/2006 and 2006/2007 growing seasons on Coffea arabica cv. Catuai Vermelho IAC 144, in a location situated at an elevation of 850 m in Coimbra, Minas Gerais, Brazil. The treatments consisted of: 1 - potassium silicate; 2 - potassium silicate + copper hydroxide; 3 - copper hydroxide; 4 - epoxiconazole formulated with pyraclostrobin and 5 - control treatment. Six applications of potassium silicate and copper hydroxide were made twice per month from December to March of each year. Two applications of the systemic fungicide were done in December and March of each year. Potassium silicate alone or in combination with copper hydroxide was not efficient in reducing coffee leaf rust incidence and increasing yield under high incidence of coffee leaf rust.

Chemical control of coffee leaf rust in Coffea canephora cv. conilon

The two species of coffee commercially harvested in Brazil and the world are Coffea arabica (Arabica coffee) and C. canephora (Conilon coffee). Coffee leaf rust, caused by Hemileia vastatrix, is the most frequent disease that affects coffee crops. However, damage has not been estimated, and the chemical control has not been determined for the Conilon coffee in Brazil. This study evaluated a new strategy to control coffee leaf rust through the application of triazole fungicides in soil and then to estimate the damage caused by the disease after treatment. To this end, an experiment was conducted in a randomized block design with eight treatments and four replications from November 2008 to May 2011. Every 30 days, leaves were collected from experimental plots to assess the disease incidence and severity. The coffee production was also evaluated between April and May each year. The disease progress curves were plotted with these data, and the area under the disease progress curve for the disease incidence and severity was calculated. The data of the incidence of disease and production were also used to estimate the damage caused by rust. The treatments with the applications in the soil were effective in controlling the disease; however, through the joint analysis of the disease’s control and productivity, the best treatments were those that used ciproconazol or flutriafol in the soil, with or without foliar sprays treatments. There were no additional benefits with the foliar fungicides in Conilon coffee. The damage caused by rust in Conilon coffee can reach 47 % if measures are not implemented to the disease control.

Efeito da aplicação foliar de silício na resistência à ferrugem e na potencialização da atividade de enzimas de defesa em cafeeiro

The major method for control of coffee leaf rust, caused by Hemileia vastatrix, is the use of fungicides. The supply of silicon (Si) to plants is an interesting control strategy because this element can increase the resistance of many plant species to pathogens. This study aimed to evaluate the effect of foliar application of Si on reducing rust severity as well as to determine if it can potentiate the activity of enzymes related to host resistance to pathogens. Coffee plants (cultivar Catuai Vermelho 44) were sprayed with distilled water, potassium silicate (KSi) solution (35 g/L, pH 10.5), KSi (35 g/L, pH 5.5), and acibenzolar-S-methyl (ASM) solution (200 µg/L) 24 hours before inoculation. There was no significant difference among the treatments regarding the content of Si and potassium in the leaf tissue. Rust severity was significantly higher on plants sprayed with water as compared to the other treatments. The ASM significantly decreased rust severity by 70% in comparison to the water spray treatment. Foliar application of KSi, regardless of the pH, was efficient in decreasing rust severity. The ASM was efficient in increasing the activity of chitinases and β-1,3-glucanases. On the other hand, the application of KSi, regardless of the pH, was inefficient to potentiate the activity of these six enzymes studied, even though it had a great impact on reducing rust severity.

Avaliação do cloreto de benzalcônio no controle da ferrugem (Hemileia vastatrix Berk. & Br.) do cafeeiro (Coffea arabica L.)

W it h the obje ct ive to e valuat e the be nzal ko ni um c hl or ide performance in programs of treatment wi th copper fungi cide and epoxiconazol to control coffee leaf rust ( Hemileia vastatrix Berk. & Br.), an experiment was lead in the Garca city, SP. They had been evaluated coffee of cultivar ‘Mundo Novo 388-6-20’ spaced at 4,0 x 1,5 m. The results obtained showed that the application of triazol fungicide was important to control coffee leaf rust, considered the main disease of the culture. Programs of control with benzalkonium Martins, A.N.; Silveira, A. P. da; Furtado, E.L. Evaluation of Benzalkonium Chloride on the control of coffee leaf rust. Summa Phytopathologica, v.35, n.2, p.145-145, 2009

Bioprospecting endophytic bacteria for biological control of coffee leaf rust

Suppression of plant diseases due to the action of endophytic microorganisms has been demonstrated in several pathosystems. Experiments under controlled conditions involving endophytic bacteria isolated from leaves and branches of Coffea arabica L and Coffea robusta L were conducted with the objective of evaluating the inhibition of germination of Hemileia vastatrix Berk. & Br., race II, urediniospores and the control of coffee leaf rust development in tests with leaf discs, detached leaves, and on potted seedling of cv. Mundo Novo. The endophytic bacterial isolates tested proved to be effective in inhibiting urediniospore germination and/or rust development, with values above 50%, although the results obtained in urediniospore germination tests were inferior to the treatment with fungicide propiconazole. Endophytic isolates TG4-Ia, TF2-IIc, TF9-Ia, TG11-IIa, and TF7-IIa, demonstrated better coffee leaf rust control in leaf discs, detached leaves, and coffee plant tests. The endophytic isolates TG4-Ia and TF9-Ia were identified as Bacillus lentimorbus Dutky and Bacillus cereus Frank. & Frank., respectively. Some endophytic bacterial isolates were effective in controlling the coffee leaf rust, although some increased the severity of the disease. Even though a relatively small number of endophytic bacteria were tested, promising results were obtained regarding the efficiency of coffee leaf rust biocontrol. These selected agents appears to be an alternative for future replacement of chemical fungicide.