Resumo Existem poucos estudos relacionados ao impacto de queimadas sobre os fungos habitantes do solo presente no cerrado. Objetivou-se com este trabalho identificar a micoflora presente em amostras de solos, antes e após o processo de queimada em duas profundidades, observando a interferência deste processo na população de fungos habitantes do solo. As amostras foram coletadas em uma área, no município de Jaú do Tocantins, Estado do Tocantins. Foram instalados bioensaios em delineamento experimental inteiramente casualizado, com quatro repetições e cinco tratamentos, representados por diferentes concentrações de solução do solo. A identificação dos fungos foi feita, em nível de gênero, de acordo com suas estruturas morfológicas formadas em meio de cultura, através de observações em microscópio ótico. Na área antes da queimada, observou-se a presença de maior diversidade de gêneros e quantidade de colônias fúngicas. O contrário foi constatado na área posteriormente submetida à queimada, que apresentou menor número de colônias fúngicas. Dos gêneros identificados, destacaram-se Aspergillus, Penicillium, Cladosporium, Fusarium, Mucor, Pythium e Trichoderma, que apresentaram maior número de colônias em quantidades representativas. Observou-se ainda uma redução em torno de 45% na população de fungos antagonistas. Foi possível constatar que o uso do fogo na vegetação influenciou negativamente as populações microbianas presentes nas camadas mais superficiais do solo de cerrado.

Abstract There are few studies related to the impact of burnings on soil fungi present in the cerrado. The aim of this work was identifying the mycoflora in cerrado soil samples before and after burning process at two depths; observing the interference of this process in the fungi soil inhabitants population. The samples were collected in area, in the municipality of Jaú do Tocantins, State of Tocantins. Bioassays were installed in a completely randomized experimental design, with four replicates and five treatments, represented by different concentrations of soil solution. The identification of the fungi was made at the genus level according to their morphological structures formed in culture medium through optical microscope observations. In the before burning area we observed greatest diversity of genera and fungi colonies. The opposite was found in the area subsequently submitted to the burning process, showing minor fungal colonies. Among the genera identified, Aspergillus, Penicillium, Cladosporium, Fusarium, Mucor, Pythium and Trichoderma were the most representative colonies. We observed a reduction of 45% approximately in the population of antagonistic fungi. It was found that the use of fire in vegetation negatively influenced microbial populations present in the surface layers of cerrado soil.

RESUMO: A ferrugem, causada pelo fungo biotrófico Olivea neotectonae, destaca-se como uma doença importante nas plantações de teca no Brasil. Considerando a importância atual dessa ferrugem e a necessidade de obter informações básicas adicionais sobre seu agente causal para melhor manejo da doença, o presente estudo teve como objetivo analisar a morfologia da O. neotectonae utilizando microscopia de luz e demonstrar o processo de infecção em folhas de teca por meio de técnicas de microscopia eletrônica de varredura (MEV). As características morfológicas observadas em microscopia de luz foram semelhantes às descritas na literatura para essa espécie. A MEV revelou que as estruturas de infecção do patógeno penetraram na folha de teca através do complexo estomático. Este estudo fornece a primeira evidência microscópica do processo de infecção de Olivea neotectonae em folhas de plantas de teca.

ABSTRACT: Rust, caused by the biotrophic fungus Olivea neotectonae, stands out as an important disease in teak plantations in Brazil. Considering the current importance of this rust and the need to obtain additional basic information about its causal agent to better disease management, the present study aimed to analyze the morphology of O. neotectonae using light microscopy and demonstrate the infection process in teak leaves using scanning electron microscopy techniques (SEM). The morphological characteristics observed using light microscopy were similar to those described in the literature for this species. SEM revealed that the infection structures of the pathogen penetrated the teak leaf through the stomata complex. This study provides the first microscopic evidence of the infection process of Olivea neotectonae in leaves of teak plants.

RESUMO A produção de mudas de teca é realizada principalmente por sementes, que é um importante veículo de transmissão de diversos patógenos. Objetivou-se com este trabalho identificar e quantificar os fungos associados às sementes de teca, a patogenicidade desses microrganismos às mudas e a transmissibilidade semente-plântula. Para o teste de sanidade foram utilizadas sementes coletadas no estado do Tocantins e outras adquiridas nos estados do Goiás (GO) e São Paulo (SP). Os tratamentos utilizados foram sementes desinfestadas e não desinfestadas, e sementes com e sem mesocarpo. O ensaio foi conduzido utilizando o método do papel de filtro (Blotter test). Para o teste de patogenicidade em mudas, foram utilizados os isolados de Fusarium sp., Botryodiplodia sp., Alternaria sp. e Plenodomus sp. Para a avaliação da transmissão de fungos via semente-plântula foram utilizadas sementes de cada local. Foram identificados os seguintes gêneros de fungos nas sementes: Fusarium, Trichoderma, Botryodiplodia, Aspergillus, Penicillium, Rhizopus, Cladosporium, Alternaria e Plenodomus. Foi observada maior ocorrência de fungos nas sementes provenientes dos estados de GO e SP. Fusarium foi o gênero fúngico com maior incidência nas sementes dos três estados. Apenas os gêneros Fusarium e Botryodiplodia foram patogênicos às mudas de teca. Houve baixa transmissibilidade semente-plântula, sendo que apenas o gênero fitopatogênico Fusarium foi transmitido.

ABSTRACT The production of teak seedlings is mainly carried out by seeds, which is an important vehicle for the transmission of various pathogens. The purpose of this study was to identify and quantify the fungi associated with teak seeds, the pathogenicity of these microrganisms to the seedlings and the seed-seedling transmission. There were used seeds collected in Tocantins state and others acquired in the states of Goias (GO) and in São Paulo (SP) for the sanity test. The treatments used were seeds disinfested and not disinfested, and seeds with and without mesocarp. The analysis was conducted using the paper filter method (Blotter test). To pathogenicity test in seedlings, were utilized the isolates of Fusarium sp., Botryodiplodia sp., Alternaria sp. and Plenodomus sp. To evaluate the fungal seedling-transmission were used seeds of each location.The following genera of fungi were identified in the seeds: Fusarium, Trichoderma, Botryodiplodia, Aspergillus, Penicillium, Rhizopus, Cladosporium, Alternaria and Plenodomus. A higher occurrence of fungi was observed in the seeds from the states of GO and SP. Fusarium was the fungal genera with the highest incidence in the seeds of the three states. Only the Fusarium and Botryodiplodia genera were pathogenic to teak seedlings. There was low seed-seedling transmission, with only the phytopathogenic genus Fusarium being transmitted.

ABSTRACT The fungal genus Curvularia is associated with a number of diseases in plants, commonly producing foliar spots in forage grasses. The objective of this study was to characterize the morphological and molecular diversity of the isolates of Curvularia sp. associated with Andropogon seeds, and to assess both their capacity to transmit disease and the pathogenicity of this fungus to crop. Ten isolates of Curvularia sp. were sourced from Andropogon seeds from agricultural producing regions in the Brazilian states Tocantins and Pará. Morphological characterization was achieved by observing fungus colonies and conidia and molecular characterization by DNA extraction and amplification with sequence-specific primers. The disease transmission was evaluated from seed sowing, in which after 40 days typical symptoms of Curvularia sp. were observed. Pathogenicity was evaluated by inoculating conidial suspension into the leaves of healthy plants, and after ten days, inspecting for pathogenic symptoms. Based on morphological and molecular features, the pathogen associated with Andropogon seeds was identified as Curvularia lunata, which, as such, is transmitted through the Andropogon plants via its seeds and is pathogenic to this species of forage grass.

ABSTRACT The objectives of this study were to evaluate the effect of lemon grass, citronella grass, Mexican-tea and noni essential oils on urediniospore germination of Olivea neotectonae , the agent responsible for rust in Teak (Tectona grandis L.f.); to evaluate the phytotoxic effect of these essential oils on teak seedlings; and to evaluate the use of essential oils to control rust in teak plants when preventively and curatively applied. We found that the noni and lemon grass essential oils inhibited 100% of urediniospore germination. On the other hand, the essential oils from noni and lemon grass caused phytotoxicity when applied to seedlings at concentrations of 2000 and 1500 μL L-1, respectively. The major constituents found in lemon grass essential oil were Geranial and Neral, while Octanoic Acid was found in noni oil. Lower values in the area below the rust progress curve were observed with the preventive application of lemon grass and noni essential oils.

RESUMO A ferrugem, causada por Olivea neotectonae, destaca-se como principal doença da teca, causando desfolha prematura em todos os estádios fenológicos da cultura. O objetivo do estudo foi avaliar o progresso temporal da ferrugem em plantas adultas de teca no sul do Estado do Tocantins. Avaliaram-se a incidência e severidade da ferrugem (escala de notas) e obtiveram-se curvas de progresso da doença, que foram ajustadas aos modelos matemáticos monomolecular, logístico e Gompertz. Correlacionaram-se os dados de incidência e severidade com as variáveis climáticas coletadas na estação meteorológica, localizada na região do estudo. A incidência da ferrugem atingiu 100% aos 98 dias a partir do início das avaliações (DIA). A maior severidade (igual ou acima de 75%) foi observada aos 147 DIA. Houve correlação negativa e significativa entre severidade e temperatura mínima. O ajuste ao modelo de Gompertz sugere que medidas de controle devem ser tomadas objetivando reduzir a taxa de progresso da doença.

ABSTRACT Rust, caused by Olivea neotectonae, stands out as the main teak disease, causing premature defoliation regardless of the tree’s growth stage. In this study, we aimed to assess the temporal progress of rust in adult teak plants in southern Tocantins State (Brazil). Both rust incidence and severity were evaluated and the disease progress curves were obtained, adjusting to monomolecular, logistic and Gompertz mathematical models. Data from incidence and severity were correlated with climate variables collected by the agrometeorological station located in the study area. Rust incidence reached 100% at 98 days after beginning of the evaluations (DBE). The highest severity (equal or above 75%) was observed at 147 DBE. There was a significant and negative correlation between severity and minimum temperature. The adjustment of the Gompertz model suggests that control measures should be aimed primarily to reduce the rate of disease progress.

ABSTRACT Identification of Thysanoptera is based mainly on external morphology examination that can be time-consuming and difficult for non taxonomic experts. In this work, we propose a rapid and efficient molecular method to identify Frankliniella schultzei, an important and widespread pest thrips vector of tospoviruses in South America countries. Species-specific primers designed in the mitochondrial cytochrome oxidase I gene (mtCOI) were optimized for detection by conventional PCR and real-time PCR. The primers were tested on immature and adult thrips collected from crops and weeds found in São Paulo State. All samples collected were identified as F. schultzei, indicating the high prevalence of this species as vector of tospoviruses in Brazilian fields.

RESUMO O feijoeiro-comum (Phaseolus vulgaris) é uma cultura de grande relevância na alimentação da população brasileira. A murcha-de-curtobacterium ou murcha bacteriana, causada por Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff). é uma doença vascular que acomete o feijoeiro causando danos significativos. Neste contexto, o objetivo deste trabalho foi avaliar a ação in vitro de Bacillus spp. na inibição de dois isolados de Cff, colonização do sistema radicular e desenvolvimento de plântulas de feijoeiro-comum. Foram realizados dois ensaios in vitro para verificar a atividade antagônica dos isolados Bacillus licheniformis, B. subtilis e B. subtilis + B. lichenformis a dois isolados de Cff. Todos os isolados de Bacillus spp. apresentaram inibição no crescimento dos isolados de Cff. Não foi observada a colonização das raízes das plântulas de feijoeiro-comum, pelos isolados bacterianos avaliados.

ABSTRACT The common bean (Phaseolus vulgaris) constitutes a very important crop in the feeding of the Brazilian population. The curtobacterium wilt or bacterial wilt, caused by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), is a vascular disease that affects the common bean, leading to significant damage. In this context, the aim of this study was to evaluate the in vitro effect of Bacillus spp. on the inhibition of two Cff isolates, the colonization of the root system and the development of common bean seedlings. Two in vitro assays were performed to verify the antagonistic activity of the isolates Bacillus licheniformis, B. subtilis, and B. subtilis + B. lichenformis against two isolates of Cff. All isolates of Bacillus spp. inhibited the growth of Cff isolates. Common bean seedlings showed no root colonization by the evaluated bacterial isolates.