RESUMO O objetivo do trabalho foi avaliar a eficácia de um extrato vegetal obtido a partir de folhas de cafeeiro infectadas por Hemileia vastatrix (NEFID), do fosfito de zinco, sulfato de zinco e da mistura desses nutrientes com o extrato NEFID, no controle do oídio em eucalipto. O experimento foi conduzido em minijardim clonal, contendo minicepas do híbrido Eucalyptus urophylla x Eucalyptus grandis (“urograndis”), considerado altamente suscetível ao oídio. Os tratamentos consistiram da aplicação do extrato NEFID, do sulfato ou fosfito de zinco e a combinação desses nutrientes com o extrato nas proporções de 50:50, 25:75 e 75:25, respectivamente. As aplicações dos tratamentos e as avaliações da severidade da doença foram feitas a cada 14 dias. Foram avaliados também os efeitos dos tratamentos sobre a produção e a porcentagem de enraizamento das mini-estacas, além da ação fungitóxica direta dos tratamentos sobre o Oidium eucalypti através da microscopia eletrônica de varredura. Todos os tratamentos foram eficientes no controle do oídio em minicepas de eucalipto, obtendo controles que variaram de 45-70% da doença. O extrato vegetal NEFID, o fosfito de zinco, a mistura desses dois produtos e o tratamento contendo 25% Sulfato de zinco + 75% NEFID foram os que obtiveram melhores controles do oídio, sendo mais eficiente que o fungicida à base de piraclostrobina + epoxiconazole usado no controle do patógeno. Verificou-se que todos os tratamentos foram fungitóxicos, causando grandes modificações na sua morfologia. Os tratamentos não afetaram negativamente a produção de mini-estacas e a porcentagem de enraizamento.

ABSTRACT The aim of this study was to evaluate the efficacy of a plant extract obtained from the leaves of the coffee tree infected Hemileia vastratrix (NEFID), zinc phosphite, zinc sulfate and the mixture of these nutrients with the extract NEFID in controlling powdery mildew in eucalyptus. The experiment was conducted in minigarden containing clonal ministumps hybrid Eucalyptus urophylla x Eucalyptus grandis (“urograndis”) acesita-144 considered highly susceptible to powdery mildew. The treatments consisted of NEFID extract, zinc sulfate or zinc phosphite and the combination of these nutrients with the extract in the proportions of 50:50, 25:75 and 75:25 respectively. The application of treatments and evaluations were made every 14 days. We also evaluated the effects of treatments on the production of cuttings and their rooting and direct fungitoxic action of treatments on Oidium eucalypti by scanning electron microscopy. All treatments were effective in controlling powdery mildew in ministumps eucalyptus, getting a control that ranged from 45-70% of the disease. The plant extract NEFID, zinc phosphite, the mixture of these two products and the treatment containing 25% zinc sulfate + 75% NEFID were those who had better control of powdery mildew, being more efficient than the fungicide pyraclostrobin + epoxiconazole used for pathogen control. It was found that all treatments were fungitoxic, causing major changes in their morphology. The treatments did not affect the production of mini-cuttings and rooting.

A new foliar disease caused by Teratosphaeria pseudoeucalypti on eucalyptus (E. globulus, E. urophylla x E. globulus and E. nitens x E. globulus) in Brazil is described . The disease is characterized by leaf spots of variable sizes and shapes, resulting in leaf blight and premature defoliation. Based on the morphological characteristics and multilocus phylogenetic analysis of the EF-1α, β-T and ITS-2 gene regions of five isolates, the fungus was identified as T. pseudoeucalypti. This is the first report of this pathogen outside Australia and a method for sporulation in culture is described.

O objetivo do trabalho foi avaliar o potencial dos óleos essenciais extraídos de Hyptis marrubioides, Aloysia gratissima e Cordia verbenacea no controle da ferrugem asiática da soja. A atividade inibitória dos óleos essenciais (aplicados no intervalo de concentração de 0,05 - 2%) sobre a germinação dos urediniósporos de Phakopsora pachyrhizi foram avaliados em teste in vitro. As propriedades curativas e erradicantes dos óleos (aplicados no intervalo de concentração de 0,05 - 0,5%) foram estudadas em casa de vegetação utilizando a cultivar MG/BR 46 (Conquista) suscetível a P. pachyrhizi. Microscopia eletrônica de varredura foi utilizado para investigar o efeito dos óleos essenciais sobre a morfologia dos urediniósporos do fungo. Os tratamentos com os óleos essenciais, em todas as concentrações testadas inibiram totalmente a germinação dos urediniósporos in vitro. A aplicação curativa dos óleos essenciais reduziu a severidade da doença, expressa em área abaixo da curva de progresso em 33 a 41%, enquanto que o fungicida comercial (piraclostrobina + epoxiconazole), empregado como controle positivo reduziu em 61%. Tratamento de plantas infectadas com óleos essenciais produziu alterações morfológicas nas estruturas fúngicas, semelhantes as produzidas pelo fungicida comercial, ou seja, murchamento dos urediniósporos, apressórios, tubos germinativos e paráfise.

The aim of this study was to evaluate the potential of essential oils derived from Hyptis marrubioides, Aloysia gratissima and Cordia verbenacea for controlling Asian soybean rust. The inhibitory activities of the essential oils (applied in a concentration range of 0.05 - 2%) on the germination of Phakopsora pachyrhizi urediniospores were investigated using in vitro assays. The curative and eradicating properties of the oils (applied in a concentration range of 0.05 - 0.5%) were studied under greenhouse conditions using the P. pachyrhizisusceptible soybean cultivar MG/BR 46 (Conquista). Scanning electron microscopy was employed to investigate the effects of the essential oils on the morphology of the P. pachyrhizi urediniospores. The treatment with the essential oils at all concentrations tested led to the total inhibition of spore germination in vitro. The curative application of the essential oils reduced the disease severity, expressed as the area under the disease-progress curves, by 33 to 41%, whereas the commercial fungicide (pyraclostrobin + epoxyconazole) employed as a positive control reduced the severity by 61%. The treatment of infected plants with the essential oils resulted in morphological alterations in the fungal structures that were similar to those produced by the commercial fungicide, namely, a shrivelling of the urediniospores, appressoria, germ tubes and paraphyses.

The aim of the study was to evaluate the antifungal activity of essential oils from "hortelã do campo" (Hyptis marrubioides), "alfazema-do-Brasil" (Aloysia gratissima) and "erva-baleeira" (Cordia verbenacea) and their efficacy in the treatment of soybean seeds infected with Colletotrichum truncatum. In vitro assays were performed to evaluate the effects of the oils on spore germination, mycelial growth, and the production and viability of C. truncatum conidia. Soybean seeds inoculated with C. truncatum were treated with essential oils at concentrations ranging from 0.5 to 2% and grown under greenhouse conditions. Seed health and germination percentages were evaluated according to standard protocols. Seedling emergence, stand establishment and the percentages of dead seedlings were determined, together with the emergence speed index, plantlet height and dry weight of aerial biomass. The oils from H. marrubioides, C. verbenacea and A. gratissima inhibited the germination and production of conidia as well as the growth of C. truncatum. At concentrations ≥ 1%, the effectiveness of the oils against soybean anthracnose was superior to, or at least comparable with, that of the fungicide carbendazim. The viability of conidia and the germination of soybean seeds were not affected by any of the treatments with essential oils. It is concluded that essential oils from H. marrubioides, A. gratissima and C. verbenacea have potential as alternatives to synthetic fungicides in the control of anthracnose in soybean seeds.

Neste trabalho, objetivou-se avaliar o efeito de extratos e óleos essenciais de quatorze plantas medicinais e ou nativas, conhecidas popularmente no Norte de Minas Gerais, sobre a germinação de esporos e crescimento micelial do fungo Colletotrichum gloeosporioides. Foram utilizados no teste de inibição do crescimento micelial, os extratos aquosos de alecrim (Rosmarinus officinalis), erva baleeira (Cordia verbenacea), joá (Solanum sisymbriifolium), quebra-pedra (Phyllanthus corcovadensis), erva botão (Eclipta alba) e açafrão da índia (Curcuma longa) obtidos por meio do processo de infusão; óleo essencial de alecrim de vargem (Família Lamiaceae), alecrim pimenta (Lippia sidoides), alfavaca cravo (Ocimum gratissimum), lippia (Lippia citriodora), goiaba branca (Psidium guajava), capim santo (Cymbopogon citratus); óleo resina de copaíba (Copaifera langsdorffi); hidrolatos de alecrim de vargem, goiaba vermelha (Psidium guajava), lippia, capim santo, goiaba branca, alfavaca cravo; manipueira de (Manihot esculenta). Também foram testados esses mesmos hidrolatos e os óleos essenciais na germinação dos esporos do fungo. Todos os tratamentos foram realizados in vitro, cultivando-se o fungo em meio de cultura BDA acrescido de 100μL dos compostos vegetais. No teste de inibição da germinação, todos os óleos essenciais impediram a germinação do fungo. No entanto, os hidrolatos não tiveram esse efeito. No teste de crescimento micelial, os óleos essenciais de todas as plantas inibiram completamente o crescimento do fungo, exceto o óleo da goiaba branca. Os extratos aquosos, a manipueira, o óleo resina e os hidrolatos, também não foram eficientes sobre o crescimento do patógeno. Esses resultados indicam o potencial antifúngico de alguns óleos essenciais de plantas medicinais.

The objective of the work was to evaluate the effect of extracts and essential oils of fourteen medicinal and or native plants popularly known in the North of Minas Gerais, on the germination of spores and the mycelial growth of Colletotrichum gloeosporioides fungus. The following were used in the mycelial growth inhibition test: the watery extracts of rosemary (Rosmarinus officinalis), Cordia verbenacea, Solanum sisymbriifolium, Phyllanthus corcovadensis, Eclipta alba, and Curcuma longa obtained through the infusion process; essential oils of "alecrim de vargem" (Lamiaceae Family), Lippia sidoides, Ocimum gratissimum, Lippia citriodora, white guava (Psidium guajava), lemongrass (Cymbopogon citratus); copaíba oil resin (Copaifera langsdorffi) as well as hydrolates of "alecrim de vargem", red guava (Psidium guajava), Lippia citriodora, lemongrass, white guava, Ocimum gratissimum; and cassava manipueira (Manihot esculenta). The same hydrolates and essential oils were also tested on the germination of the fungus spores. All the treatments were carried out in vitro, cultivating the fungus in PDA supplemented with 100μL of the vegetal compounds. In the germination inhibition test, all the essential oils prevented the germination of the fungus. However, the hydrolates did not have this effect. In the mycelial growth test, the essential oils of all of the plants completely inhibited the fungus growth, except the white guava oil. The watery extracts, the cassava manipueira, the oil resin and hydrolates were also not efficient in preventing the growth of the pathogen. These results indicate the fungitoxic potential of some essential oils of medicinal plants.