ABSTRACT The objective of this work was to evaluate the ability of Trichoderma asperellum isolates and their culture filtrates to control Lasiodiplodia theobromae in vivo and to promote the growth of pecan seedlings. Two experiments were carried out, both in a greenhouse. In the first experiment, the aerial part of the plants was sprayed by biological control treatments and, 14 days later, the pathogen was inoculated into the stem, through injury. In the second experiment, the substrate was moistened with biological control treatments and 14 days later the pathogen was inoculated following the same methodology as the first experiment. The following parameters were evaluated: length of the aerial part, stem diameter, fresh mass of the aerial part and the root, dry mass of the aerial part and the root, incidence and severity of the disease. The comparison of means was performed using the Skott-Knott test at a 5% probability of error, using the SISVAR software. In both experiments, the greatest responses were obtained in the growth parameters evaluated in the treatments with the culture filtrates and with the spore suspension in relation to the treatment inoculated with the pathogen without the use of biological control treatments. These treatments also reduced the incidence and severity of stem canker in pecan seedlings, and the best treatment varied with the form of application. The isolates of T. asperellum and the culture filtrates stimulated the initial growth of the plants, decreasing the incidence and severity of stem canker in pecan plants, regardless of the form of application.

RESUMO O objetivo deste trabalho foi avaliar a ação de isolados de Trichoderma asperellum e de seus filtrados de cultura no controle de Lasiodiplodia theobromae in vivo e na promoção do crescimento de mudas de nogueira-pecã. Foram desenvolvidos dois experimentos, ambos em casa de vegetação. No primeiro experimento, a parte aérea das plantas foi aspergida pelos tratamentos de controle biológico e 14 dias após foi inoculado o patógeno no caule, por meio de ferimento. No segundo experimento, o substrato foi umedecido com os tratamentos de controle biológico e 14 dias após foi feita a inoculação do patógeno seguindo mesma metodologia do primeiro experimento. Foram avaliados os seguintes parâmetros: comprimento da parte aérea, diâmetro do caule, massa fresca da parte aérea e da raiz, massa seca da parte aérea e da raiz, incidência e severidade da doença. A comparação das médias foi realizada pelo teste de Skott-Knott a 5% de probabilidade de erro, com o software SISVAR. Nos dois experimentos, obtiveram-se as maiores respostas nos parâmetros de crescimento avaliados nos tratamentos com os filtrados de cultura e com a suspensão de esporos, em relação ao tratamento inoculado com o patógeno sem o uso dos tratamentos de controle biológico. Esses tratamentos também reduziram a incidência e a severidade do cancro do tronco em mudas de nogueira-pecã, sendo que o melhor tratamento variou com a forma de aplicação. Os isolados de T. asperellum e os filtrados de cultura estimularam o crescimento inicial das plantas, diminuíram a incidência e a severidade do cancro do tronco nas plantas de nogueira-pecã, independente da forma de aplicação.

Abstract Yerba mate (Ilex paraguariensis) crop is susceptible to many disease-causing agents that affect a plant, like a root rot, reducing its productivity. The present study aimed to evaluate the in vitro antagonist potential of Trichoderma sp. on Fusarium oxysporum, the causal agent of root rot in yerba mate. Four Trichoderma spp. isolates and one Fusarium oxysporum isolate were used. The antagonistic action of Trichoderma spp. on F. oxysporum was evaluated through the dual cultures and volatile metabolites tests. The results of the dual cultures assay revealed that Trichoderma spp. inhibited the mycelial growth of Fusarium oxysporum, with percent inhibition ranging from 13.06 to 14.24%. Moreover, in the volatile metabolites test, T. tomentosum and T. harzianum showed the best inhibition results, 27.70 and 24.46%, respectively. Thus, Trichoderma spp. presented in vitro antagonist potential in the control of Fusarium oxysporum.

Resumo A cultura da erva-mate está exposta a doenças que prejudicam o desenvolvimento da planta, reduzindo a produtividade. Dentre essas doenças têm-se a podridão-de-raízes causada por Fusarium spp. O objetivo deste trabalho foi avaliar a ação antagonista in vitro de Trichoderma spp. sobre Fusarium oxysporum, agente causal da podridão-de-raízes em erva-mate. Foram utilizados quatro isolados de Trichoderma spp. e um isolado de Fusarium oxysporum. A ação antagônica de Trichoderma spp. sobre F. oxysporum foi avaliada por meio do teste de pareamento de culturas e de metabólitos voláteis. No teste de pareamento de culturas, os isolados de Trichoderma spp. inibiram o crescimento micelial de Fusarium oxysporum, com percentual de inibição que variou de 13,06% a 14,24%. No teste de metabólitos voláteis, T. tomentosum e T. harzianum apresentaram os melhores resultados de inibição, com 27,70% e 24,46%, respectivamente. Assim, pode-se concluir que Trichoderma spp. apresenta ação antagonista in vitro contra F. oxysporum, agente causal da podridão-de-raízes em erva-mate.

Resumo O controle biológico é uma importante ferramenta para o controle de insetos-praga pelas inúmeras vantagens apresentadas e por diminuir os riscos ambientais provocados pelas técnicas de controle químico. No entanto, são escassos estudos referentes à morfofisiologia de microrganismos utilizados nesse método de controle, principalmente no que se refere ao Oncideres impluviata, principal inseto-praga da acácia-negra. Assim, o objetivo do presente estudo foi realizar a caracterização morfofisiológica de isolados de Beauveria bassiana e Metarhizium anisopliae, como uma potencial alternativa para o controle biológico do anelador-da-acácia-negra. Para tanto, foram utilizados cinco isolados de fungos entomopatogênicos (três isolados de Beauveria bassiana e dois de Metarhizium anisopliae) e avaliados o crescimento micelial, esporulação, coloração e caracterização dimensional dos conídios em diferentes meios de cultura (BDA, V8CaCO3 e meio completo). Os isolados de Beauveria bassiana apresentaram melhor crescimento micelial no meio V8CaCO3 e maior esporulação no meio de cultura completo; o micélio aéreo se apresentou de cor branca em todos os isolados. Em relação aos isolados de Metarhizium anisopliae, o maior crescimento micelial e esporulação ocorreram no meio de cultura completo e a coloração do micélio aéreo variou entre tons de cinza e verde-oliva. Esses resultados vêm a gerar informações preliminares a respeito do uso de fungos entomopatogênicos para o controle do anelador-da-acácia-negra.

Abstract Biological control is a useful tool for insect pests control due to the many advantages set out and further to reduce the environmental risks caused by chemical control techniques. However, there is a gap in the scientific literature that describes microorganisms' morphophysiology used in this control method, especially in Oncideres impluviata, the main pest insect of black wattle (Acacia mearnsii De Wild.). Thus, this study aimed to perform morphophysiology characterization of isolates of Beauveria bassiana and Metarhizium anisopliae as a potential alternative for the biological control of twig girdler of black wattle. So, five isolates of entomopathogenic fungi (three isolates of Beauveria bassiana and two of Metarhizium anisopliae) were used. Also, mycelial growth, sporulation, staining was evaluated. Additionally, a dimensional characterization of conidia in different culture media (BDA, V8CaCO3, and complete medium) was carried out. Beauveria bassiana isolates showed better mycelial growth in the V8CaCO3 medium and greater sporulation in the complete culture medium; the aerial mycelium presented a white color in all isolates. These results allow producing preliminary information regarding the use of entomopathogenic fungi for the control of the twig girdler of black wattle.

RESUMO A nogueira-pecã [Carya illinoinensis (Wangenh.) K. Koch] é uma espécie arbórea amplamente difundida na região sul do Brasil e comercialmente importante devido à produção de nozes e madeira. Cancros do tronco em árvores de noz-pecã impactam negativamente o pomar, mas as causas bióticas dos cancros geralmente não são identificadas. Sintomas de cancro do caule foram observados em cerca de 60% das nogueiras de pomares em municípios do Rio Grande do Sul e Paraná. Assim, este estudo teve como objetivo analisar as características moleculares e morfofisiológicas de fungos isolados de cancros em nogueira-pecã em pomares do sul do Brasil e confirmar sua patogenicidade na planta. Amostras de caules sintomáticos foram coletadas e possíveis agentes causais foram isolados. A identificação molecular foi realizada pela técnica de Reação em Cadeia da Polimerase para amplificação da região EF-1α e posterior sequenciamento. O sequenciamento, seguido de aspectos morfofisiológicos do crescimento micelial e pigmentação da colônia, permitiu a identificação de um complexo de espécies incluído na família Botryosphaeriaceae. Os isolados foram classificados como Lasiodiplodia theobromae, Pseudofusicoccum kimberleyense e Neofusicoccum parvum. A patogenicidade foi testada inoculando os isolados em mudas de nogueira-pecã para avaliar os sintomas. Todos os isolados causaram cancro no caule, mas houve variação na severidade. Portanto, diferentes espécies da família Botryosphaeriaceae são responsáveis pela ocorrência de cancro em tronco de nogueira-pecã na região sul do Brasil, mas em diferentes níveis de dano. Assim, é crucial identificar e compreender o comportamento dos isolados fúngicos para melhor controlar os cancros nos pomares.

ABSTRACT Pecan tree [Carya illinoinensis (Wangenh.) K. Koch] is a widespread species in the southern region of Brazil and commercially important for nut and wood production. Stem cankers in pecan trees negatively impact the orchard, but the biotic causes of cankers are usually not identified. Symptoms of stem canker were observed in about 60% of pecan trees from orchards in the states of Rio Grande do Sul and Paraná. Therefore, this study aimed to analyze the molecular and morphophysiological characteristics of fungi associated with pecan canker in orchards in southern Brazil and to confirm their pathogenicity in pecan seedlings. Samples from symptomatic stems were collected in different municipalities and possible causal agents were isolated. Molecular identification was performed by the Polymerase Chain Reaction technique for amplification of the EF-1α region and subsequent sequencing. The sequencing, followed by morphophysiological aspects of mycelial growth and colony pigmentation, allowed the identification of a species complex included in the Botryosphaeriaceae family. The isolates were classified as Lasiodiplodia theobromae, Pseudofusicoccum kimberleyense and Neofusicoccum parvum. Pathogenicity was tested by inoculating the isolates into pecan seedlings to evaluate the symptoms. All isolates caused canker in the stem, but there was variation in the severity. Therefore, different species of the Botryosphaeriaceae family are responsible for stem canker occurrence in pecan trees in the southern region of Brazil, but at different levels of injury. Thus, it is crucial to identify and understand the behavior of the fungal isolates to best control cankers in pecan orchards.

Resumo Juglans regia e Carya illinoinensis, ambas da família Juglandaceae, são espécies de nogueiras conhecidas mundialmente pela produção das chamadas nozes, com crescente expansão da área cultivada na América do Sul. Entretanto, nos últimos anos houve aumento da incidência de doenças nessas espécies, o que compromete a rentabilidade dos cultivos e a qualidade do produto. Colletotrichum nymphaeae foi recentemente identificado no Brasil causando danos em frutos de Juglans regia. Este estudo teve como objetivo avaliar o potencial de infecção cruzada de C. nymphaeae, isolado de frutos sintomáticos de Juglans regia, em folíolos e frutos de cultivares de Carya illinoinensis. Para isso, discos de meio de cultura contendo estruturas do patógeno foram depositados sobre folíolos e frutos de seis e três cultivares de Carya illinoinensis, respectivamente. Colletotrichum nymphaeae mostrou-se patogênico tanto em folíolos como em frutos de todas as cultivares avaliadas, sendo que as maiores lesões em folíolos foram observadas nas cultivares ‘Barton’, ‘Melhorada’ e ‘Imperial’, enquanto que a cultivar ‘Shawnee’ demonstrou menor suscetibilidade ao patógeno. Nos frutos, a cultivar ‘Imperial’ mostrou-se mais suscetível ao patógeno, já que apresentou as maiores lesões.

Abstract Juglans regia and Carya illinoinensis, both from the Juglandaceae family, are species known worldwide for the production of edible nuts, with an increasing expansion of the cultivated area in South America. However, in recent years there was an increase in the incidence of diseases in the species, which compromises the profitability of crops and the nut quality. Colletotrichum nymphaeae was recently identified in Brazil causing damage to fruits of Juglans regia. This study aimed to evaluate the potential for cross-infection of Colletotrichum nymphaeae, isolated from symptomatic fruits of Juglans regia, on leaves and fruits of Carya. illinoinensis cultivars. Disks of culture medium containing structures of the pathogen were deposited on leaflets and fruits of six and three cultivars of Carya illinoinensis, respectively. Colletotrichum nymphaeae was found to be pathogenic both in leaflets and in fruits of all the cultivars evaluated, with the largest lesions in leaflets observed in the cultivars ‘Barton’, ‘Melhorada’ and ‘Imperial’, while the cultivar ‘Shawnee’ demonstrated less susceptibility to the pathogen. In the fruits, ‘Imperial’cultivar was more susceptible to the pathogen, since it presented the largest lesions.

Resumo Nas regiões Centro-Oeste e Sul do Brasil, a cultura da erva-mate (Ilex paraguariensis) constitui-se uma importante fonte de extrativismo florestal, além de diversificar a renda, principalmente na agricultura familiar. A erva-mate, como outras espécies florestais, é infectada por diversos patógenos, como o gênero Fusarium, causador da podridão-de-raízes. Os patógenos possuem ampla variabilidade genética, mesmo dentro de um único gênero e dentro de uma única espécie, resultado de adaptações ao meio em que vivem. Este estudo teve como objetivo avaliar o sequenciamento das regiões do genoma ITS e β-tubulina na identificação em nível de espécie dos isolados de Fusarium spp. patogênicos à erva-mate, e identificar a formação de grupos de compatibilidade vegetativa (VCG) entre os isolados de Fusarium spp. patogênicos à erva-mate. O sequenciamento das regiões ITS e β-tubulina consolidou a separação entre os sete isolados patogênicos em F. solani e F. oxysporum. Para esses isolados, a técnica para obtenção de mutantes nit foi adequada para a classificação fenotípica, fundamentais nos testes de VCG para espécies de Fusarium, sendo obtidos cinco VCG.

Abstract In the central-western and southern regions of Brazil, the cultivation of yerba mate (Ilex paraguariensis) is considered an important source of forest extraction, besides providing an alternative income, especially for families. The yerba mate, like other forest species, is infected by several pathogens, such as fungi of the genus Fusarium, causing root rot. Pathogens have wide genetic variability, even within a single genus and species, resulting from adaptations to their environments. This study aimed at characterizing molecularly isolated Fusarium spp. through the sequencing of the ITS and β-tubulin genome regions, identifying the species level as well as the formation of vegetative compatibility groups (VCG) among these isolates of the root rot pathogen in yerba mate. The sequencing of the ITS and β-tubulin regions, defined the separation between the seven pathogenic isolates of F. solani and F. oxysporum. For the same isolates, the technique to obtain nit mutants was suitable for the phenotypic classification, obtaining five VCGs for species of Fusarium, root rot in yerba mate.

ABSTRACT This study aims to report two species of Scolytinae that have been damaging Carya illinoinensis trees in southern Brazil. In two Brazilian municipalities, Guarapuava in Paraná State and Pantano Grande in the Rio Grande do Sul State, insects of the Scolytinae family were found damaging pecan trees. Infested tree samples were kept in the laboratory in glass tubes sealed with a voile tissue until the emergence of adults. After the adults’ emergence, the specimens were identified by their morphological characteristics and sent to a taxonomist specialized in Scolytinae family for identification. The species Xyleborus retusus was identified causing damages to pecan trees from Guarapuava while the species Xyleborus ferrugineus was identified in pecan trees from Pantano Grande. Trees injured by these insects displayed similar symptoms in both study areas. In Guarapuava and Pantano Grande, 13 and 10 trees, respectively, died due to stem lesions caused by Xyleborus spp. Thus, this study reports for Brazilian pecan growers the occurrence of Scolytinae species X. retusus and X. ferrugineus damaging C. illinoiensis plants in southern Brazil. It also emphasizes the importance of constant crop monitoring to minimize the risk of pest damage.

Abstract Brown leaf spot disease, caused by the fungus Ragnhildiana diffusa, is responsible for losses in pecan orchards and quantification is essential in order to conduct epidemiological studies to establish levels of productivity losses, and assess control strategies. Therefore, the aim of this study was to develop and validate a diagrammatic scale for assessing the severity of brown leaf spot in pecan. 240 symptomatic leaflets were collected from adult trees in Anta Gorda, in the Brazilian state of Rio Grande do Sul, and used to assess the current percentage severity of the disease. The scale was based on the minimum and maximum observed severity of the disease, with six graduations defined according to the Weber-Fechner Visual Stimulus Law. The scale therefore consisted of eight levels (1.5, 4.6, 10.6, 17.3, 39.5, 65.1, 77.5, and 98%). The estimates of eight evaluators provided a basis for validating the scale. They made estimates of disease severity on 40 symptomatic digitalized pecan leaflets first, without using the scale and then referring to it. The scale provided greater precision, accuracy, and reproducibility of estimates and should result in more reliable epidemiological studies.

RESUMO O ergosterol é responsável por importantes funções na membrana plasmática dos fungos. A influência de agentes fungitóxicos no conteúdo de ergosterol na membrana é um dos mecanismos mais importantes de ação antifúngica e seu conhecimento permite a geração de produtos que associam compostos ativos de diferentes mecanismos, consequentemente, melhorando a eficácia dos conservantes de madeira. Portanto, este estudo otimizou um método para quantificar ergosterol em fungos apodrecedores da madeira. As espécies de podridão-branca selecionadas foram Ganoderma applanatum e Trametes versicolor, enquanto que as de podridão-parda foram Gloeophyllum trabeum e Lentinus lepideus. Discos miceliais de cada espécie foram transferidos para placas de Petri contendo meio batata-dextrose-ágar coberto por celofane. O micélio de cada fungo foi coletado, pesado e transferido para tubos de ensaio com 5 mL de hidróxido de potássio alcoólico 25%. Os tubos foram agitados em vortex por 5 min, submetidos a ultrassom por 5 min, incubados a 85 °C por 4 h, seguido da adição de 2 mL de água destilada estéril e 5 mL de n-heptano e subsequente agitação em ultrassom por 2 min. A camada de n-heptano foi analisada por espectrofotometria no UV entre 230 e 300 ηm. O branco continha apenas n-heptano. A massa micelial úmida dos fungos variou de 0,061 a 0,296 g. O teor de ergosterol foi de 0,007% para Lentinus lepideus e 0,004% para as demais espécies. A absorbância foi maior que a observada no branco para todas as amostras. O método adaptado foi eficiente para extração de ergosterol.

ABSTRACT Ergosterol is responsible for important functions in the fungal plasma membrane. The influence of fungitoxic agents on membrane ergosterol content is one of the most important mechanisms of antifungal action and its knowledge allows the generation of products that associate active compounds of different mechanisms, consequently improving the effectiveness of wood preservatives. Therefore, this study optimized a method for quantifying ergosterol in wood-decay fungi. The white-rot species selected were Ganoderma applanatum and Trametes versicolor, while the brown-rot were Gloeophyllum trabeum and Lentinus lepideus. Mycelial discs of each species were transferred to Petri dishes containing a cellophane-covered potato-dextrose-agar medium. Mycelia of each fungus were collected, weighed, and transferred to test tubes with 5 mL of 25% alcoholic potassium hydroxide. The tubes were vortexed for 5 min, subjected to ultrasound for 5 min, incubated at 85 °C for 4 h, followed by the addition of 2 mL of sterile distilled water and 5 mL of n-heptane and subsequent ultrasound shaking for 2 min. The n-heptane layer was analyzed by UV spectrophotometry between 230 and 300 ηm. The blank sample only contained n-heptane. The mycelia wet weight of the fungi ranged from 0.061 to 0.296 g. Ergosterol content was 0.007% for Lentinus lepideus and 0.004% for the other species. The absorbance was higher than the ones observed in the blank for all samples. The adapted method was efficient for ergosterol extraction.

Abstract Pecan cultivation in Brazil has gained increasingly economic importance in the southern part of the country. The objective of this work was to identify the pathogen that causes root rot in Carya illinoinensis seedlings in the nursery, through morphological, molecular and pathogenicity tests. Fungi from the genus Fusarium found in symptomatic roots of pecan seedlings were isolated in potato dextrose agar (PDA) culture medium and purified. Morphological characterization was performed in PDA and carnation leaf agar (CLA) media. For the molecular characterization, the genomic segments ITS (internal transcribed spaces), β-tub (beta-tubulin), and tef1-α (elongation fact 1-alpha) were sequenced. The pathogenicity test was performed on healthy seedlings in the greenhouse. The combination of morphological and molecular characters was fundamental for identification of the species, showing that the most suitable genes for identification were ITS and tef1-α. The causative agent of root rot in C. illinoinensis seedlings in the nursery was identified as Fusarium oxysporum.

ABSTRACT The safflower (Carthamus tinctorius L.) has a wide diversity of use, such as feeding, oil extraction and floral stems for ornamentation. However, it has low productivity due to the high susceptibility to attack by pathogenic microorganisms during its culture. For this reason, seed treatment is an alternative for protection and to guarantee sanitary quality. The objective of the present work was to determine the effect of leaf powder from three plant species on the physiological and sanitary quality of safflower seeds (Carthamus tinctorius L.) stored for different periods of time. The experiment was carried out in a completely randomized design, in 10x3 factorial (leaf powder combinations and seed storage periods), with four repetitions. The seed lot was stored with an average moisture content of 9%. Leaves of Melia azedarach L., Dendranthema grandiflora Tzvelev and Tagetes erecta L. were dried and crushed to obtain powder that was applied to the seeds at the doses of: zero (control), 1, 2 and 3 g kg-1 of seeds. Seed quality was evaluated through germination, seedling length and mass, emergence and health tests. The use of leaf powder from M. azedarach, D. grandiflora and T. erecta as a treatment of safflower seeds was beneficial for the control of the infestation by phytopathogenic fungi and increased its potential for germination and emergence in the field. The results indicated that it have potential for the treatment of safflower seeds stored for different periods of time.

RESUMEN El cártamo (Carthamus tinctorius L.) presenta una amplia diversidad de uso, como alimentación, extracción de aceite y vástagos florales para ornamentación. Sin embargo, presenta baja productividad debido a la alta susceptibilidad al ataque de microorganismos patógenos durante su cultivo. Por ello, el tratamiento de semillas es una alternativa para la protección y garantizar la calidad sanitaria. El objetivo del presente trabajo fue determinar el efecto de polvo de hojas de tres especies de plantas sobre la calidad fisiológica y sanitaria de semillas de cártamo (Carthamus tinctorius L.) almacenados por diferentes períodos de tiempo. El experimento fue realizado en un diseño completamente al azar, en factorial 10x3 (combinaciones de polvo de hojas y períodos de almacenamiento de semillas), con cuatro repeticiones. El lote de semillas fue almacenado con grado de humedad promedio del 9%. Hojas de Melia azedarach L., Dendranthema grandiflora Tzvelev y Tagetes erecta L. se secaron y trituraron hasta obtener polvo que se aplicó a las semillas a las dosis de: cero (control), 1, 2 y 3 g kg-1 de semillas. Se evaluó la calidad de las semillas a través de las pruebas de germinación, longitud y masa de plántulas, emergencia y sanidad. El uso de polvo de hojas a partir de M. azedarach, de D. grandiflora y T. erecta como tratamiento de semillas de cártamo fue benéfico para el control de la infestación por hongos fitopatógenos e incrementó su potencial de germinación y de emergencia en el campo. Los resultados indicaron que tienen potencial para el tratamiento de semillas de cártamo almacenadas por diferentes períodos de tiempo.

RESUMO A erva-mate (Ilex paraguariensis) tem grande importância socioeconômica na agricultura familiar do Sul do Brasil. A principal doença da erva-mate é a podridão-de-raízes causada por Fusarium spp. Pouco se sabe a respeito da fisiologia deste patógeno, principalmente quanto à agressividade associada à produção de enzimas extracelulares. Neste trabalho, avaliou-se a agressividade de isolados de F. oxysporum e F. solani patogênicos à erva-mate e determinou-se as atividades das enzimas extracelulares catalase, lacase, celulase, caseinase, amilase, protease, lipase e pectinases produzidas por Fusarium spp. em meio de cultura. Foram utilizados seis isolados de F. solani e um isolado de F. oxysporum patogênicos à erva-mate. O isolado de F. oxysporum mostrou-se menos agressivo em relação aos demais isolados de F. solani. Todos os isolados de Fusarium spp. produziram, de maneira semiquantitativa, as enzimas extracelulares catalase, lacase, celulase, caseinase, amilase, protease, lipase e pectinases (poligalacturonase e pectato liase). Entretanto, a quantidade produzida de cada enzima foi significativamente diferente entre os isolados. Com exceção das enzimas lacase e poligalacturonase o isolado M7C1 de F. solani exibiu as maiores médias do índice enzimático e foi também o responsável pelo maior percentual de morte de mudas de erva-mate.

ABSTRACT The yerba-mate (Ilex paraguariensis) has great socioeconomic importance on family farming in Southerm Brazil. One of the main yerba-mate disease is root rotting, caused by Fusarium spp. Little is known about the pathogen physiology, especially regarding the aggressiveness associated with the production of extracellular enzymes. On this work, the aggressiveness of isolates of F. oxysporum and F. solani pathogenic to yerba-mate was evaluated and it was determined the activities of extracellular enzymes catalase, laccase, cellulase, caseinase, amylase, protease, lipase and pectinases produced by Fusarium spp. in culture medium. Six isolates of F. solani and one isolate of F. oxysporum pathogenic to yerba-mate were used. The F. oxysporum isolate proved to be less aggressive in relation to the other F. solani isolates. All isolates of Fusarium spp. produced, on a semiquantitative manner, the extracellular enzymes catalase, laccase, cellulase, caseinase, amylase, protease, lipase and pectinases (polygalacturonase and pectate lyase). However, the quantity produced for each enzyme was significantly different among the isolates. With the exception of the laccase and polygalacturonase enzymes, the M7C1 isolate showed the highest enzymatic index and was also responsible for the highest percentage of yerba-mate seedlings death.

ABSTRACT Pecan is susceptible to the occurrence of diseases capable of harming its development, and leaf spot caused by Cladosporium spp is among them. Therefore, the objective of this work was to analyze the potential antagonist and in vitro effect of volatile metabolites of Trichodermaspp. On Cladosporium spp. isolated from pecan leaf spots. Three Cladosporium spp. isolates and two commercial products based on Trichodermaspp. were used, as well as an isolate of the same genus provided by the 'ElocyMinussi' Laboratory of Phytopathology at UFSM. Cladosporium spp. mycelial growth was monitored in order to evaluate the morphological characteristics of the pathogen. The use of Trichoderma spp. as biocontrol was assessed through dual culture tests and production of volatile metabolites. Trichoderma spp. showed positive results in inhibiting the growth of Cladosporium spp., thereby presenting potential to be used as a biocontrol agent.

RESUMO O objetivo deste trabalho foi avaliar o comportamento de isolados de Ceratocystis fimbriata obtidos de kiwi (Actinidia deliciosa) em mudas de acácia-negra (Acacia mearnsii De Wild.), o potencial de biocontrole in vitro de Bacillus subtilis sobre C. fimbriata e o comportamento in vivo de B. subtilis contra C. fimbriata em mudas de acácia-negra. Isolados de C. fimbriata obtidos e identificados em plantios de kiwi foram utilizados em testes de patogenicidade em mudas de A. mearnsii. O potencial antagônico in vitro de B. subtilis sobre o patógeno foi analisado em testes de confrontação direta. Para avaliar o comportamento in vivo de B. subtilis, as mudas de acácia-negra foram inoculadas com Rizolyptus® sete dias antes e após a inoculação do patógeno. Nas mudas de acácia-negra os isolados de C. fimbriata exibiram percentuais de severidade que variam de 44,15% a 100%. Nos testes de confrontação direta as cepas mostraram-se eficientes no biocontrole in vitro sobre os isolados de C. fimbriata. In vivo, o produto Rizolyptus® não foi eficiente no controle de C. fimbriata.

ABSTRACT The aim of this study was to evaluate the effect of Ceratocystis fimbriata isolates, obtained from Actinidia deliciosa (kiwifruit), on black wattle (Acacia mearnsii De Wild.) seedlings, the potential biological control exerted in vitro by Bacillus subtilis on C. fimbriata, and the in vivo effect of B. subtilis against C. fimbriata on black wattle seedlings. Isolates of C. fimbriata obtained and identified from kiwi plantations were used in pathogenicity tests on A. mearnsii seedlings. In vitro, the antagonistic potential of B. subtilis on the pathogen was analyzed by direct confrontation tests. To evaluate the effect of B. subtilis in vivo, black wattle seedlings were inoculated with Rhizolyptus® seven days before and after pathogen inoculation. On black wattle seedlings, C. fimbriata isolates caused 44,15% to 100% severity. Direct confrontation tests revealed that the strains were effective in the biological control of C. fimbriata isolates in vitro. In vivo, Rizolyptus® was not efficient in controlling C. fimbriata.

ABSTRACT The cultivation of yerba-mate (Ilex paraguariensis) has been intensified in the State of Rio Grande do Sul, as result of the valuation of the price paid to the producer. However, studies related to Fusarium pathosystem vs. yerba-mate are still insufficient, so that many producers have faced significant losses in herbal production due to the occurrence of the roots rotting. Considering the above, the objectives of this study were: a) morphologically characterize the Fusarium spp. isolates collected in sick plants of yerba-mate; b) select efficient morphological characters on separating the Fusarium spp. isolates in similarity groups; c) identify the Fusarium spp. isolates to species level through the sequencing of the genomic region of elongation factor 1-α (TEF-1α); and d) testing the pathogenicity of the Fusarium spp. isolates selected based on the morphological characterization. For such, collections for the pathogen isolates were made in five cities and the collection points were georeferenced. Thirty-nine isolates were morphologically characterized by variables as mycelial growth, sporulation, macroconidia length and width, microconid format, colonies pigmentation and formation of chlamydospore, and tested for pathogenicity by substrate inoculation. The variables used in the morphological characterization were efficient in discriminating the isolates in seven groups, especially length of macronidia associated to sporulation. Seven pathogenic isolates of Fusarium spp. were identified, also through molecular sequencing of the TEF-1α gene region. The sequencing of the TEF-1α region consolidated the identification of pathogenic isolates as F. solani and F. oxysporum.