Currently, Xanthomonas axonopodis is one of the main foliar pathogens for Eucalyptus spp. in Brazil. It induces leaf blight and defoliation of seedlings in the nursery and young plants in the field. However, little is known about thefavorable conditions for infection. The establishment and development of bacterial leaf blight caused by X. axonopodis in eucalyptus was studied for different leaf ages, temperatures and leaf wetness durations. Disease severity increased with leaf age, and the highest severity was observed on the fourth pair of completely expanded leaves (from the apex to the base). A higher level of bacterial colonization was also observed on the fourth pair of leaves quantified as bacterial cells/cm2 of leaf area. Twelve hours of free water on the leaf surface, prior to inoculation, was essential to promote a severe infection. However, with the increase in the leaf wetness duration, a decrease in disease severity was observed. The optimal temperature for disease development was 26-30ºC.

Eucalyptus plantations cover approximately 5.1 million hectares of Brazil, an area that will likely increase given the demand for natural products from planted forests. In recent years, anthracnose diseases have been frequently found on eucalyptus in Brazilian nurseries. In 2012, rooted mini-cuttings of clones of E. urophylla x E. grandis ("urograndis") exhibiting leaf spot and stem girdling symptoms were collected from nurseries in the Brazilian states of Pará and Minas Gerais, and cultures of Colletotrichum were obtained from the lesions. The isolates were initially identified to species of the C. gloeosporioides species complex, according to searches of the Q-bank Fungi database with the DNA sequences of their internal transcribed spacer (ITS) regions. Subsequent phylogenetic analysis of the β-tubulin (TUB2) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) regions, combined with morphological characterization, allowed us to conclude that the fungus belongs to C. theobromicola. Conidial suspension sprayed on "urograndis" clone plants induced similar symptoms as those found under natural conditions. Re-isolation of the fungus from symptomatic plants fulfilled the Koch´s postulate. To our knowledge, this is the first report of C. theobromicola in Brazil.

Several species of Calonectria cause diseases on a wide range of forest tree species that are propagated either via seedlings or rooted cuttings. In nurseries these fungi cause damping-off, cutting and root rots, stem lesions, and leaf blights. Recently a Calonectria sp. was isolated from rooted cuttings of Anadenanthera peregrina (Fabaceae), Piptadenia gonoacantha (Fabaceae), and Azadirachta indica (Meliaceae) exhibiting leaf blight and cutting rot in a forest nursery at the Universidade Federal de Viçosa, Brazil. Morphological comparisons and DNA sequences of three loci containing partial gene sequences of β-tubulin (TUB2), calmodulin (CAL), and elongation factor (TEF-1α) indicated that these isolates represent an unnamed species of Calonectria, described here as C. hodgesii sp. nov. Sprayinoculated plants of all three hosts with a suspension at 1x10(4) conidia mL-1 induced leaf lesions, cutting rot, and intense defoliation as observed under natural conditions. Calonectria hodgesii was re-isolated from infected tissue, which fulfilled Koch's postulates and confirmed its status as a pathogen with a wide host range.

Calonectria pteridis is one of the most important causal agents of Calonectria leaf blight (CLB) of Eucalyptus spp. in Brazil, which is a limiting factor for growth of Eucalyptus plantations. In this study we developed standard procedures for in vitro mass spore production and inoculation of C. pteridis for screening plant species and clones for resistance to CLB. The isolates used in this study were identified using similarity in DNA sequence to reference strains. Among six media tested, glucose asparagine agar induced the highest sporulation production and a significantly enhanced sporulation was found by scraping the aerial mycelium and temporarily submersing the cultures in tap water, followed by drying and additional incubation of the culture. We also demonstrated that the severity of CLB on excised leaves of two Eucalyptus spp. clones increased significantly when the inoculated leaves were incubated in the dark. The optimal temperature for infection was 26ºC when plants were incubated for 48 hours post-inoculation in a mist chamber and then maintained in a greenhouse (25ºC±5ºC) for 50 days. This study identifies environmental conditions to improve spore production and inoculation procedures of C. pteridis for selection of resistant Eucalyptus spp.

Contaminated irrigation water constitutes one of the main sources of plant pathogens that can cause disease and lead to potentially significant production losses in forest nurseries. Recycling of contaminated irrigation water increases the risk of spreading diseases. The objective of this study was to evaluate a simple slow sand filtration treatment of irrigation water as a method for eradicating fungal and bacterial pathogens in eucalypt cutting nurseries. Pilot filter units were constructed from PVC pipes containing a 80 cm high layer of sand with grain size varying from 0.50 to 0.75 mm, drainage layers of 10 cm of fine gravel (4 mm) followed by a 15 cm layer of coarse gravel (8 mm), connected to a water outlet. The PVC pipe had space for a 150 mm water column above the sand layer and the filter had a flow rate of 100 to 300 L m-2 h-1. Eradication of the bacterial pathogen Ralstonia solanacearum, and the fungal pathogens Cylindrocladium candelabrum and Botrytis cinerea through the use of the filter was evaluated. Detection of bacteria in filter-treated irrigation water was performed through the micro drop method followed by PCR of colonies, while fungal pathogens were detected using a castorbean leaf biological bait method. Evaluations were performed daily 35 times for R. solanacearum, 25 times for C. candelabrum and 18 times for B. cinerea during a period of 12 months. After the last evaluation period, samples from various depths of the sand layer in the filters were taken and analyzed for the presence of the plant pathogens. The slow sand filters were able to remove B. cinerea and C. candelabrum spores with 100% efficiency while eradication of R. solanacearum colonies reached up to 99.6%. Colonies of Trichoderma sp. were found predominantly on the all filter layers. The results of this study show that slow sand filters are efficient for recycled water in eucalypt nurseries, especially in eradicating fungal pathogens.

Objetivou-se, neste estudo, determinar os efeitos da posição da folha, superfície foliar e os sítios de entrada, assim como ferimentos, lesões de outros patógenos ou aberturas naturais sobre a infecção de Quambalaria eucalypti em Eucalyptus spp. Para isso, realizaram-se inoculações artificiais em folhas de mudas seminais de Eucalyptus globulus e dois clones híbridos de Eucalyptus (UFV-100 – E. grandis x E. urophylla e UFV-101 - E. saligna x E. maidenii). E. globulus foi mais suscetível à infecção que os clones UFV-100 e UFV-101. Os ferimentos artificiais favoreceram a penetração do patógeno. Entretanto, lesões velhas causadas por Cylindrocladium pteridis e Puccinia psidii não foram sítios de entrada de Q. eucalypti. Não foram observadas diferenças na germinação de esporos e colonização entre folhas em expansão e completamente expandidas. Q. eucalypti penetrou em folhas com ferimentos. Contudo não foi possível observar a penetração direta através da epiderme. Folhas jovens foram mais suscetíveis à infecção de Q. eucalypti que folhas completamente expandidas no terço superior da planta. A infecção ocorreu preferencialmente na superfície abaxial da folha.

The objectives of this study were to determine the effects of leaf position, surface, and the need for entry sites, such as wounds, other pathogen lesions or natural openings, to promote infection of Quambalaria eucalypti in Eucalyptus spp. We carried out a series of artificial inoculations in wounded and unwounded leaves from seedlings of Eucalyptus globulus and two hybrid clones (UFV-100 - E. grandis x E. urophylla and UFV-101 - E. saligna x E. maidenii). E. globulus was more susceptible to infection than clones UFV-100 and UFV-101. Artificial wounds greatly favored pathogen penetration. However, old lesions caused by Cylindrocladium pteridis and Puccinia psidii did not provide infection sites for Q. eucalypti. Differences in fungal spore germination and leaf surface colonization were not observed between expanding and fully expanded leaves. Q. eucalypti penetrated through the wounded leaves and we didn't observe direct penetration thought the epidermis. Stomata neither attracted nor repelled germ tube and somatic hyphae. Young expanding leaves were more susceptible to Q. eucalypti infection than fully expanded leaves located in the upper third of the plant. Infection took place preferentially on the abaxial leaf surface.

Avaliou-se a eficiência de rizobactérias promotoras do crescimento de plantas (PGPR) no controle biológico de Cylindrocladium candelabrum e Rhizoctonia solani, agentes causais da podridão de miniestacas de eucalipto. A inibição " in vitro" do crescimento micelial dos patógenos variou com o isolado de rizobactéria e meio de cultura. De forma geral, os isolados FL2 (Pseudomonas sp.) e 3918, S1 e S2 (Bacillus subtilis) foram os mais eficientes. Sob condições de viveiro, o isolado Ca (Pseudomonas fulva) reduziu a incidência da podridão de miniestacas, causada por C. candelabrum, em 33% em relação à testemunha e 26,7%, em relação à imersão de miniestacas no fungicida (epoxiconazole + pyraclostrobin: 0,4 g.L-1 i.a.). A densidade de inóculo de C. candelabrum no substrato reduziu a partir de 10 dias para todos os isolados de rizobactérias testados. A partir de 15 dias, o isolado Ca foi o mais eficiente na redução da densidade de C. candelabrum e na indução do enraizamento de miniestacas e no crescimento de mudas de eucalipto. Para R. solani, não houve diferença entre os tratamentos quanto à incidência da doença. Em outro experimento, observou-se ampla variação de resposta dos isolados de rizobactérias aos fungicidas testados. Tebuconazole inibiu completamente o crescimento de 80% dos isolados testados, enquanto epoxiconazole + pyraclostrobin inibiu apenas o crescimento do isolado S1. O isolado S1 foi o mais sensível e os isolados 3918 e MF2 os mais resistentes para a maioria dos princípios ativos testados. O isolado S1 foi selecionado para estudos de controle biológico em condições de viveiros de eucalipto.

The effectiveness of ten plant growth-promoting rhizobacteria (PGPR) was evaluated for the control of mini-cutting rot of eucalyptus caused by Cylindrocladium candelabrum and Rhizoctonia solani. Inhibition of the " in vitro" mycelial growth of each pathogen differed with PGPR isolate and culture medium evaluated. The most effective group of isolates was FL2 (Pseudomonas sp.), 3918, S1 and S2 (Bacillus subtilis). Under nursery conditions, isolate Ca (Pseudomonas fulva) reduced the incidence of mini-cutting rot caused by C. candelabrum by 33% compared to the control, and by 27% compared to a fungicide treatment (epoxiconazole + pyraclostrobin: 0.4 g.L-1). Inoculum density of C. candelabrum in the eucalyptus rooting medium decreased significantly beginning at 10 days after the medium was treated with the PGPR isolates. Isolate Ca was the most efficient in reducing the C. candelabrum inoculum at 15 days and in promoting rooting and growth of eucalyptus. For R. solani, no differences in disease incidence were found among treatments. Sensitivity of the PGPR isolates to ten fungicides differed widely. Tebuconazole completely inhibited 80% of the isolates, but epoxiconazole + pyraclostrobin only inhibited the S1 isolate. Isolate S1 was the most sensitive and isolates 3918 and MF2 the most resistant to the majority of active ingredients tested. Isolate Ca was selected for biological control studies in eucalyptus nursery conditions.

A mancha foliar bacteriana do eucalipto caracteriza-se inicialmente por lesões encharcadas do tipo anasarca, internervurais, angulares e anfígenas, concentradas ao longo da nervura principal, nas margens da folha ou distribuídas aleatoriamente sobre o limbo. Com o progresso da doença, as lesões adquirem aspecto ressecado e coloração marrom a palha, podendo conter orifícios no centro da lesão ou áreas recortadas do limbo em conseqüência do aborto da área necrosada, principalmente em folhas mais jovens. Eventualmente pode haver necrose em pecíolo e ramos. A doença culmina com a desfolha devido à senescência precoce das folhas infectadas. O diagnóstico inequívoco é realizado por meio de exsudação de pus bacteriano a partir de fragmento de folha infectada, sob microscópio óptico de luz (200 x). Vinte e cinco isolados oriundos dos estados do Amapá (2), Bahia (4), Minas Gerais (2), São Paulo (9), Pará (3), Mato Grosso do Sul (1) e Rio Grande do Sul (4) indutores de reação de hipersensibilidade em plantas não-hospedeiras e, patogênicos ao eucalipto em testes de injeção de suspensão bacteriana no mesófilo foliar, foram identificados por meio de testes bioquímicos, utilização de fontes de carbono e seqüenciamento do rDNA16S. Dez foram identificados como Xanthomonas axonopodis, quatro como X. campestris, quatro como Pseudomonas syringae, dois como P. cichorii, dois como P. putida, um como Erwinia sp. e dois foram similares a gêneros da família Rhizobiaceae. Nos testes de inoculação por atomização de suspensão bacteriana, apenas isolados de P. cichorii, X. axonopodis e os similares a membros da família Rhizobiaceae foram patogênicos a eucalipto. X. axonopodis é provavelmente o agente etiológico predominante da mancha foliar bacteriana de Eucalyptus spp., no Brasil.

Bacterial leaf blight of eucalyptus is initially characterized by water soaked, angular, amphigenous and interveinal lesions, concentrated along the main vein, at the edges or scattered on the leaf blade. As the disease progresses, the lesions become brown to pale, and when young leaves are infected leaf cut areas at the edges or perforations at the center of the lesions may appear due to abortion of the necrotic area. Eventually, necrosis may be found on petiole and twigs. Leaf fall commonly occurs on highly susceptible genotypes due to the early senescence of diseased leaves. Precise diagnosis is accomplished by bacterial exudation from leaf sections placed in a water drop under light microscope (200 x). Twenty-five bacterial isolates from Amapá (2), Bahia (4), Minas Gerais (2), São Paulo (9), Pará (3), Mato Grosso do Sul (1), and Rio Grande do Sul (4) States, which induced hypersensitive reaction (HR) in non-host plants and were pathogenic to eucalyptus, when inoculated by inoculum injection, were identified by biochemical assays, using carbon sources (MicroLogTM BIOLOG) and sequence analysis (16S rDNA). Ten isolates were identified as Xanthomonas axonopodis, four as X. campestris, four as Pseudomonas syringae, two as P. putida, two as P. cichorii, one as Erwinia sp., and two were similar to bacterial genera of Rhizobiaceae. When spray inoculated on intact plants of eucalyptus, only X. axonopodis, P. cichorii and isolates of the Rhizobiaceae family induced typical symptoms of the disease and were considered pathogenic. In Brazil, X. axonopodis seems to be the most widespread species causing the bacterial leaf blight of Eucalyptus spp.

Avaliou-se o risco do reaproveitamento de água não tratada, originária do efluente do minijardim clonal, da casa de vegetação, da casa de sombra, das áreas de crescimento e rustificação a céu aberto de um viveiro clonal de eucalipto, quanto ao potencial de disseminação de inóculo de Botrytis cinerea e Cylindrocladium candelabrum. Avaliou-se também a presença de inóculo desses fungos em brita usada como cobertura do piso das áreas do viveiro. Para a detecção dos patógenos, empregaram-se discos de folhas de mamoneira (Ricinus communis) como isca. Análises periódicas evidenciaram que ambos os patógenos são constantemente veiculados na água não tratada, proveniente das diferentes fases da propagação clonal e sobre a brita, sendo C. candelabrum mais freqüentemente constatado. A composição e a concentração de sais de três soluções nutritivas, expressa em valores de condutividade elétrica (0, 0,5, 1,0, 1,5, 2,0, 2,5 e 3,0 mS.cm-1), não afetaram significativamente a germinação de conídios.

The risk posed by reuse of untreated water for irrigation, collected from the effluents of mini-hedges, greenhouses, shade houses, growing and hardening areas of a eucalyptus cutting nursery, was evaluated in relation to the dissemination of Botrytis cinerea and Cylindrocladium candelabrum. The presence of inocula of these fungi was also evaluated on gravel used as soil cover. For pathogen detection, leaf discs of castor bean (Ricinus communis) were employed as biological bait. Periodical analyses of water samples, collected in the nursery effluents, and of gravel, showed that both pathogens are frequently disseminated in the water of the effluents and the gravel used as soil cover, although C. candelabrum is most common. The composition and salt concentration of three nutrient solutions, expressed in electric conductivity values (0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mS.cm-¹) did not affect conidial germination of these two fungi.

Quambalaria eucalypti foi recentemente relatado como agente etiológico da mancha foliar e do anelamento da haste de Eucalyptus spp., no Brasil. Em vista do pouco conhecimento disponível sobre este patossistema, procurou-se, neste trabalho, avaliar o crescimento micelial e a esporulação do fungo em diferentes meios de cultura, determinar "in vitro" a temperatura ótima para o crescimento micelial, esporulação e a germinação de conídios, avaliar a influência do regime de luz sobre a germinação de conídios e determinar a influência do binômio temperatura - tempo de câmara úmida sobre a severidade da doença. As temperaturas de 25, 13 e 37 ºC foram respectivamente, ótima, mínima e máxima, para o crescimento. A temperatura ótima para esporulação foi de 25 ºC. A interação entre meios de cultura e isolados foi significativa, sendo que os meios de batata-dextrose-ágar (BDA), V8-ágar (V8) e caldo de vegetais-ágar foram os mais favoráveis ao crescimento micelial, seguidos de caseína hidrolizada ágar e ágar água. Todavia, para a esporulação, a interação entre meios de cultura e isolados não foi significativa e o meio de BDA foi o mais favorável à esporulação do patógeno. A temperatura e o regime de luz não afetaram significativamente a germinação de conídios, com uma taxa média de 85 % de germinação. A interação entre temperatura e tempo de permanência em câmara úmida não foi significativa para severidade da doença. O modelo quadrático foi o que melhor representou a severidade em função da temperatura, com ponto ótimo estimado igual a 27 ºC. O modelo exponencial foi o que melhor representou a severidade em função do tempo de câmara úmida.

Quambalaria eucalypti was recently reported as the causal agent of leaf spot and stem curl in Eucalyptus spp. in Brazil. Given the scarcity of knowledge available on this pathosystem our objectives were to evaluate the "in vitro" mycelial growth and sporulation of this fungus in different culture media, determine the optimum temperature of mycelial growth, sporulation and conidial germination, evaluate the influence of the lighting regime on conidial germination and determine the combined influence of time and temperature in a moisture chamber on the disease severity. Temperatures of 25, 13 and 37 ºC were found to be the optimum, minimum and maximum for growth, respectively. The optimum temperature for sporulation was 25 ºC. The interaction between growth medium and isolates was significant and potato dextrose-agar (PDA), V8-agar (V8) and vegetable broth-agar produced the most mycelial growth, followed by hydrolyzed casein-agar and water-agar. On the other hand, the interaction between culture medium and isolates was not significant for sporulation, although PDA appeared to favor spore production by this pathogen. Temperature and lighting regime did not significantly affect conidial germination, with 85 % of medium rate. The interaction between temperature and time of exposition in a moisture chamber was not significant for severity of disease. A quadratic model best represented disease severity as a function of temperature, with estimated optimum 27 ºC. An exponential model best represented disease severity as a function of moisture chamber.

Espécies de Rhizoctonia causam queima foliar em brotações de jardim clonal e podridão de estacas durante o enraizamento, que podem limitar a clonagem do eucalipto, por estaquia. Diante da importância do patógeno para a cultura e da falta de estudos sobre a diversidade de isolados, esse trabalho objetivou caracterizar isolados e relatar novos grupos de anastomose de Rhizoctonia spp. em jardim clonal de eucalipto. Os isolados obtidos nas diferentes fases de propagação por estaquia foram caracterizados quanto ao número de núcleos nas células vegetativas, agrupados segundo as características morfológicas das colônias e identificados quanto aos grupos de anastomose, incluindo auxotrofia por tiamina. Avaliou-se, também, a virulência ao eucalipto e o efeito da temperatura no crescimento micelial dos isolados. Não se detectou correlação entre os agrupamentos morfológicos e reações de anastomose. Constatou-se, também, que a população de Rhizoctonia spp., nos solos de jardins clonais, é constituída por ampla gama de isolados, predominantemente binucleados, com diferentes graus de virulência a eucalipto. Os isolados binucleados e os multinucleados, tiveram a mesma tendência de crescimento em relação à temperatura, com ótimo para a taxa de crescimento entre 25-30 ºC. Observou-se, pela primeira vez, isolados de R. solani AG2-2 IIIB e os binucleados de Rhizoctonia spp., AG-P e AG-O, como agentes etiológicos da podridão de estacas em casa de vegetação, e os isolados binucleados AG-A e AG-L em solo de jardim clonal de eucalipto.

Rhizoctonia spp. cause shoot and leaf blight of eucalyptus in clonal hedges as well as cuttings. Despite the importance of Rhizoctonia spp. to eucalyptus, little is known about their diversity. Thus, we characterized isolates and report new anastomosis groups in a eucalyptus clonal hedge. Isolates obtained at different stages of cutting propagation were characterized according to the number of nuclei in vegetative cells, grouped by morphological characteristics of the colony, anastomosis group, and thiamine auxotrophism. The isolates were also evaluated for virulence on eucalyptus and effect of temperature on their mycelial growth. No correlation between morphological grouping and anastomosis reaction was detected. A wide range of isolates, predominantly binucleate, forms the population of Rhizoctonia spp. present in the soil of clonal hedges, which differed in virulence to eucalyptus. Binucleate and multinucleate isolates had similar growth features at different temperatures, with an optimum growth rate between 25-30 ºC. Isolates of R. solani AG2-2 IIIB and binucleate isolates of Rhizoctonia spp., AG-P and AG-O, as agents of cutting rot, and binucleate isolates AG-A and AG-L in the soil of eucalyptus clonal hedge are reported for the first time.

A queima de folhas em brotações em jardim clonal e a mela de estacas na fase de enraizamento, causadas por espécies de Rhizoctonia, podem limitar a produção de mudas de eucalipto por estaquia. Apesar de sua importância, pouco se conhece sobre essas doenças. Assim, visando otimizar as estratégias de controle dessas doenças, nesse trabalho objetivou-se elucidar aspectos da dinâmica populacional de Rhizoctonia spp. no solo e em brotações, a fim de estabelecer, correlações com a incidência da doença, bem como determinar a distribuição do patógeno em jardim clonal de eucalipto. Conclui-se que há flutuação populacional de Rhizoctonia spp. em jardim clonal de eucalipto, sendo observado um padrão de distribuição espacial agregado do inóculo no solo. A dinâmica populacional de Rhizoctonia spp. foi correlacionada à temperatura, mas não à precipitação pluviométrica.

Leaf blight in shoots of clonal hedges and web blight of cuttings for rooting, caused by Rhizoctonia species, may be limiting to the production of eucalyptus seedlings by cuttings. Despite their importance, there have been few etiological and epidemiological studies of these diseases. To optimize disease management strategies, this research aimed to evaluate population dynamics of Rhizoctonia spp. in soil and eucalyptus cuttings to correlate with disease incidence, and to determine spatial distribution of Rhizoctonia spp. inoculum in a clonal nursery of eucalyptus cuttings. Population fluctuation of Rhizoctonia spp. was detected throughout the year. Pathogen distribution in soil was found to have an aggregated pattern. Temperature, but not rainfall, was correlated to population levels of Rhizoctonia spp in soil samples.

Várias espécies de Cylindrocladium podem causar doenças em mudas de eucalipto, na propagação clonal. Apesar de, em algumas situações, fungicidas serem imprescindíveis no controle desses patógenos, faltam estudos para avaliar a efetividade desses produtos. Por isso, objetivou-se selecionar fungicidas sistêmicos para controlar C. candelabrum, determinar o efeito protetor, curativo e anti-esporulante dos fungicidas, sua translocação e persistência em plantas de eucalipto. Nos experimentos in vitro foram testados: azoxystrobin (AZO), triadimenol (TRI), boscalid (BOS), pyraclostrobin (PYR), carbendazim (CAR), tetraconazole (TET), tebuconazole (TEB), epoxiconazole+pyraclostrobin (EPO-PYR) e epoxiconazole (EPO) nas concentrações 0,1, 1, 5, 10, 50, 100 e 1000 µg de i.a/mL. Nos experimentos in vivo, utilizou-se um clone suscetível a C. candelabrum (Eucalyptus grandis x E. urophylla). Excetuando-se o estudo da atividade translaminar, aplicaram-se os fungicidas, em ambas as faces do limbo foliar. Após 24 h, as plantas foram inoculadas com suspensão de 10(5) conídios/mL de C. candelabrum. Testou-se o efeito protetor dos fungicidas, em diferentes concentrações: AZO (0,2; 0,25; 0,4; 0,65 e 0,8 g/L), EPO (0,75; 1,125; 1,5; 1,875 e 2,25 mL/L), EPO-PYR (1,25; 1,875; 2,5; 3,125 e 3,75 mL/L), PYR (0,75; 1,125; 1,5; 1,875 e 2,25 mL/L) e TEB (0,75; 1,125; 1,5; 1,875 e 2,25 mL/L), selecionados nos testes in vitro. Para avaliar o efeito curativo, anti-esporulante, a persistência e a atividade translaminar, utilizaram-se os fungicidas: AZO (0,4 g/L), EPO (1,5 mL/L), EPO-PYR (2,5 mL/L) e TEB (1,5 mL/L). Obteve-se efeito protetor, curativo e anti-esporulante com EPO, EPO-PYR e TEB, os quais tiveram atividade translaminar e persistência nos tecidos foliares.

Several Cylindrocladium species may cause diseases in eucalyptus mini-cuttings. Although the use of fungicides is sometimes indicated, there are few studies evaluating fungicides in eucalyptus nurseries. Therefore, systemic fungicides were used against C. candelabrum to evaluate their protective, curative, and antisporulating effects, as well as their translocation and persistence in eucalyptus plants. Under in vitro conditions, azoxystrobin (AZO), triadimenol (TRI), boscalid (BOS), pyraclostrobin (PYR), carbendazim (CAR), tetraconazol (TET), tebuconazol (TEB), epoxiconazol +pyraclostrobin (EPO-PYR) and epoxiconazol (EPO), were used in the following concentrations: 0,1, 1, 5, 10, 50, 100 and 1000 µg a.i/mL. For the in vivo experiment, a clone (Eucalyptus grandis x E. urophylla) susceptible to C. candelabrum was used. The fungicides were sprayed on both leaf sides (except for the translaminar activity evaluation), the plants were allowed to dry out for 24 h, and inoculated with a 10(5) conidia/mL suspension. Protective effect of AZO (0.2; 0.25; 0.4; 0.65 and 0.8 g/L), EPO (0.75; 1.125; 1.5; 1.875 and 2.25 mL/L), EPO-PYR (1.25; 1.875; 2.5; 3.125 and 3.75 mL/L), PYR (0.75; 1.125; 1.5; 1.875 and 2.25 mL/L) and TEB (0.75; 1.125; 1.5; 1.875 and 2.25 mL/L), was evaluated at different concentrations. In subsequent experiments, the following fungicides (concentrations) were used: AZO (0.4 g/L), EPO (1.5 mL/L), EPO-PYR (2.5 mL/L) and TEB (1.5 mL/L). The fungicides EPO, EPO-PYR and TEB promoted protective, curative, and antisporuling effects, as well as translaminar translocation and persistence in the leaves.

A seca-da-mangueira, causada pelo fungo Ceratocystis fimbriata, é uma doença endêmica no município de São Fidelis, no norte do Estado do Rio de Janeiro. Ceratocystis fimbriata foi encontrado associado a árvores de pinha (Annona squamosa) apresentando sintomas de seca dos ramos. Isolados obtidos de pinha e manga, originários da mesma região, apresentaram a mesma morfologia e sequências espaçadoras ITS do rDNA similares. Estas seqüências foram também similares a de outros isolados brasileiros de C. fimbriata sensu stricto. Inoculações cruzadas dos isolados de pinha e manga resultaram no desenvolvimento de sintomas em ambas espécies de plantas. Este é o primeiro relato de A. squamosa como hospedeira de C. fimbriata.

Mango branch blight disease, caused by Ceratocystis fimbriata, is endemic to the municipality of São Fidelis in northern Rio de Janeiro State. In addition to mango, C. fimbriata was found associated with sugar apple trees (Annona squamosa) showing symptoms of branch blight in São Fidelis. Sugar apple and mango isolates from the same region had the same morphology and showed similar ITS-rDNA sequences. These sequences were also similar to other Brazilian isolates of C. fimbriata sensu stricto. Cross inoculation of such isolates obtained from diseased sugar apple and mango resulted in diseased symptoms on both plant species. This is the first record of A. squamosa as a host for C. fimbriata.

A incidência da murcha bacteriana, causada por Ralstonia solanacearum, em viveiros clonais de eucalipto, no período de abril a setembro de 2005, resultou no descarte de cerca de 553.991 minicepas, 6.837.691 propágulos na fase de enraizamento e 11.266.819 mudas, nos Estados da Bahia, do Espírito Santo, do Maranhão, de Minas Gerais e do Pará, totalizando um prejuízo estimado em, no mínimo, seis milhões de reais (US$ 2,7 milhões). Em minijardim clonal, a doença caracteriza-se por necrose foliar, escurecimento anelar ou completo do lenho, murcha e morte de minicepas. Os sintomas na parte aérea são similares à morte gradual de minicepas submetidas a podas drásticas ou com sistema radicular malformado. Na fase de enraizamento, miniestacas infectadas podem apresentar arroxeamento das nervuras do limbo foliar e podridão. No campo, a doença caracteriza-se por bronzeamento e necrose foliar, desfolha basal, ascendente escurecimento interno do lenho e morte da planta, geralmente a partir do quarto mês após o transplantio. Os sintomas geralmente se agravam em árvores com enovelamento de raízes e afogamento de coleto. A etiologia da doença foi confirmada por meio de testes de exsudação, microscopia de varredura, isolamento da bactéria, análises de PCR/RFLP, reação de hipersensibilidade (HR) em mudas de fumo, testes de patogenicidade em plântulas de eucalipto e tomate e re-isolamento da bactéria. Como o sistema de produção de mudas clonais de eucalipto é altamente favorável à multiplicação bacteriana e na falta de conhecimento sobre a resistência genética e de outras estratégias de controle da doença, é essencial evitar a introdução da bactéria em viveiros.

The occurrence of bacterial wilt caused by Ralstonia solanacearum in eucalyptus clonal hedges in the Brazilian states of Bahia, Espírito Santo, Maranhão, Minas Gerais and Pará, from April to September, 2005 resulted in loss of 553,991 rooted cuttings, 6,837,691 cuttings at rooting stage and 11,266,819 cuttings, with a total loss estimated to be at least six million reais (US$ 2.7 M). In clonal minihedges, the disease is characterized by foliar necrosis, annular or complete wood darkening, wilt and death of rooted-cuttings. Leaf symptoms are similar to those observed during the gradual death of rooted-cuttings subjected to drastic pruning or with malformed root systems. In the rooting phase, infected minicuttings can present redning of leaf blade veins and cutting rot. In the field, the disease is characterized by leaf browning and necrosis, basal leaf loss, internal wood darkening and plant death, with onset generally occurring four months after transplant. Disease severity is generally higher in trees with entangled roots and overplanting. The causal agent of the disease was confirmed through exudate tests, scanning electron microscopy, bacterial isolation, PCR/RFLP analyses, hypersensitive reactions (HR) in tobacco seedlings, pathogenicity tests in eucalyptus and tomato plantlets and reisolation of the bacteria. The production of cuttings offers a highly favorable environment for bacterial multiplication. This, combined with the lack of knowledge on genetic resistance and other disease control strategies, makes it essential to avoid introduction of this bacterium in clonal nurseries.