Maria Heloisa Duarte de Moraes

Potencial de compostos orgânicos voláteis antimicrobianos no controle de Sclerotinia sclerotiorum em sementes de feijão

abstract − The objective of this work was to evaluate the potential of an artificialmixture of volatile organic compounds (VOCs), produced by Saccharomyces cerevisiae , to control Sclerotinia sclerotiorum in vitro and in bean seeds. The phytopathogenic fungus was exposed, in polystyrene plates, to an artificialatmosphere containing a mixture of six VOCs formed by alcohols (ethanol, 3‑methyl‑1‑butanol, 2‑methyl‑1‑butanol and phenylethyl alcohol) and esters (ethyl acetate and ethyl octanoate), in the proportions found in the atmosphere naturally produced by yeast. Bean seeds artificiallycontamined with the pathogen were fumigated with the mixture of VOCs in sealed glass flasksfor four and seven days. In the in vitro assays, the compounds 2‑methyl‑1‑butanol and 3‑methyl‑1‑butanol were the most active against S. sclerotiorum , completely inhibiting its mycelial growth at 0.8 µL mL -1 , followed by the ethyl acetate, at 1.2 µL mL -1 . Bean seeds fumigated with the VOCs at 3.5 µL mL -1

Eficiência do fungicida carboxin + thiram no tratamento de sementes de amendoim

Fungicide seed treatment is a cheap insurance for peanut seed producers and growers. Correct fungicide use can contribute to better performance of the propagation material, increasing the yield. The objective of this research was to evaluate the efficiency of carboxin + thiram and the viability of the use of vegetable oil and an organo-sillicone based surphactant as fungicide vehicle for seed-borne fungi control. Two doses of carboxin + thiram (50 + 50 and 70 +70 g a.i./100 kg seeds) prepared in water, plus one dose ( 50 + 50 g a.i./100 kg ) mixed with the vegetable oil and the surphactant were tested. The evaluation was based on seed germination and vigour and further field establishment of the crop. It was verified that the most important benefits of seed treatment were the significative reduction of dead seeds and the pre-emergence damping-off. Both doses of fungicide prepared in water were efficient for the control of seed-born pathogens, except for Rhizopus sp. The vegetable oil and the surphactant provided better covering and adherence of the fungicide to seeds, increasing the efficiency for the control of Aspergillus spp and Penicillium spp. No phytotoxic effect of the fungicide and the vehicle agents was detected on the peanut seeds.

Controle químico de Fusarium moniliforme em sementes de milho: metodologia de avaliação e efeitos sobre a qualidade fisiológica

The objectives of this study were to evaluate the effect of light regimes on the mycelial growth of Fusarium moniliforme in fungicide-amended culture medium; to select the best light regime to detect F. moniliforme in treated corn (Zea mays) seeds and the variable to be used; and the effect of treatment on seed health and physiological quality. The fungicides evaluated were: fludioxonil + metalaxyl-m (three concentrations), difenoconazole, acibenzolar-S-methyl e captan + thiabendazole. For evaluation of mycelial growth, fungicides were added to the culture medium at three concentrations (100, 10 and 11 aeg/ml). Inoculated plates were incubated at 20±2 oC, under three light conditions: total darkness, white light and near ultraviolet light (12 h of light/12 h of darkness). In order to evaluate the effect of light on fungicide-treated seeds, a deep freezing test was carried out and seeds were incubated under the same conditions as the former test; seed health test was evaluated by measuring disease incidence and severity. Two seed samples were treated and submitted to seed health, germination, seedling emergence rates in greenhouse and cold tests. In vitro tests indicated that white light decreased the effect of the active ingredients fludioxonil + metalaxyl-m and captan + thiabendazole. The health test did not show this effect. Severity of the disease was found to be the most sensitive variable to distinct efficacy of fungicides in controlling F. moniliforme in corn seeds. The results found for both the two seeds samples suggested that: a) Fusarium moniliforme does not affect the physiological quality of corn seeds; b) the fungicide that controlled the pathogen in seeds was captan + thiabendazole, followed by fludioxonil + metalaxyl-m (97.2 g + 147.86 g/l); c) Pythium sp. was controlled by captan + thiabendazole and by fludioxonil + metalaxyl-m at the three concentrations.

Qualidade sanitária e germinação de sementes de Pterogyne nitens Tull. (Leguminosae - Caesalpinioideae)

Pterogyne nitens Tull. (Leguminosae Caesalpinioideae), wood species native to the Atlantic Rain Forest, is constantly used to extract timber. With the need to amplify the cultivation surface for trade, the interest in information about the quality and conservation of its seeds has increased. In spite of the great economic importance of this species, studies about the health quality of seeds are inexistent, mainly for native species. This paper aims to identify the occurence of pathogens associated in Pterogyne nitens seeds. The fungi were studied in a blotter test with and without freezing and symptoms in seedlings. The following fungi were found in seeds: Aspergillus sp., Penicillium sp., Fusarium moniliforme, Alternaria alternata, Rhizopus sp., Cladosporium sp. and Phoma sp. The largest occurence found was the fungi Aspergillus and Penicillium. The blotter test with freezing made it possible to identify two species of the potentially pathogenic Fusarium moniliforme and Alternaria alternata. Symptoms in seedlings were not detected.

Tratamento de sementes de pau-brasil com fungicidas: efeito na incidência de fungos, germinação e transmissão de fungos pelas sementes

ABSTRACT The objectives of this work were to evaluate the fungicidetreatment in fungi control in brazil-wood seeds and with captan,benomyl and carboxin+thiram in brazilian-wood seeds, verifyingthe fungi control and to make the transmission test of fungi byseeds. The results showed that the fungi found were Pestalotiopsis sp . , Cladosporium cladosporioides , Phoma sp. and Fusarium spp.All fungicides were efficient in the incidence of fungi, except for Fusarium spp. In relation to normal seedlings percentage thereLisboa-Padulla, T.; Moraes, M.H.D.; Menten, J.O.M.; Barbedo, C.. Brazil-wood seeds treatment with fungicide: effect in fungi incidence,germination and transmission of fungi by seeds. Summa Phytopathologica, v.35, n.2, p.148-150, 2009 Keywords: treatment, pathogenicity, Pestalotiopsis sp., Cladosporium cladosporioides. Palavras-chave adicionais: tratamento, patogenicidade, Pestalotiopsis sp., Cladosporium cladosporioides. RESUMO Os objetivos deste trabalho foram avaliar a eficiencia de fungicidasno controle de fungos em sementes de pau-brasil, efeitos na germinacaodas sementes e a transmissibilidade destes fungos para plântulas. Osresultados mostraram que os fungos incidentes foram

Levantamento da micoflora presente em grãos ardidos e sementes de milho

In maize crop, ear rot caused by fungi is one of the main responsible for quality and production losses, mainly because of the development of the so called discolored grains. The purpose of this study was to identify the mycoflora present in grains and kernels produced in different regions and climatic zones of Brazil during summer and winter harvest and relate the occurrence of fungi with such parameters. The identification of the fungi was done by the filter paper with freezing method. Two hundred grains/kernels for sample totaling 44 samples of discolored grains and 12 of kernels were analyzed. The tests were performed under a stereomicroscope and an optical microscope. The main fungi found in this survey, both in kernel and discolored grains were Penicillium sp., Fusarium spp., Aspergillus spp., Cladosporium sp. Cephalosporium sp. and Stenocarpella spp. Among the major pathogens, Fusarium spp. and Penicillium spp. were found in higher incidence in grains and kernels in both seasons. There were no significant differences between regions and climates in the summer season for Fusarium spp. and Penicillium sp. incidence. However, during the winter season there has been observed a higher incidence of Fusarium spp. in the region CO. Cladosporium sp. stood out among fungi especially during the winter season.

Detecção de fungos em sementes de pau-brasil (Caesalpinia echinata) coletadas durante sua formação e dispersão

Brazilwood, also known as Pau-Brasil or Pernambuco, (Caesalpinia echinata Lam. Syn. Guilandina echinata (Lam.) Spreng.) is a Brazilian forest tree species which has important commercial uses but is at present listed as an endangered species by the International Union for Conservation of Nature (IUCN). Removal of brazilwood from the IUCN endangered species list is important roe its continued comercial utilization. Tropical forest species are propagated by several mechanisms but seeds are one of the main processes, which means that the health and physiological quality of the seeds of such species are important factors in their propagation. Our objective was to verify the incidence of fungi during the formation and dispersion of C. Echinata seeds because there are few accounts regarding the incidence of fungi in C. Echinata seeds and the reports that do exist do not clarify the point in seed formation when fungal infection occurs. We used the health-test to analyze seeds collected at different seed formation stages (post-anthesis and dehiscence). The main fungi detected being Cladosporium cladosporioides, Pestalotiopsis maculans and Epicoccum sp, with a lower incidence of Aspergillus sp, Fusarium sp., Nigrospora sp. and Penicillium sp. We found that C. cladosporioides and P .maculans were present in seeds since the beginning of seed formation, at the 40 days post-anthesis collection, and that the incidence of fungi increased with time reaching 100% in seeds with one and two days of dehiscence. We detected Fusarium sp. in seeds collected after dehiscence and the incidence increased while the seeds remained in contact with soil.

Efeito de fungicidas para controle da ferrugem asiática na qualidade de sementes de soja

The residual effect was assessed of fungicides to control Asian rust (Phakopsora pachyrhizi) in soybean seeds of the BRS-133 cultivar using 13 treatments (without fungicide, Priori + Nimbus, Aproach + Nimbus, Priori Xtra + Nimbus, Sphere + Aureo, Opera, Stratego + Aureo, Nativo + Aureo, Impact Duo + Oppa, Celeiro + Iharol, Battle + Oppa, Aproach Prima + Nimbus, Folicur ). The residual effect of the fungicides was analyzed by the germination test, accelerated aging, germination in sand and the seed health test. The treatments did not change the quality of the seeds and the treatment Battle + Oppa was efficient to control the pathogen Cercospora kikuchii on the seeds.

Interferência da assepsia em sementes de pimentão submetidas ao teste de envelhecimento acelerado

The objective of this study was to assess the incidence of fungi and asepsis interference in sweet pepper seeds submitted to incubation for the accelerated aging test (traditional with salt solution). Samples from five different batches of Magali R cultivar sweet pepper were used, submitted or not to asepsis with 1% NaOCl for three minutes, incubated or not to 41oC for 72 hours in saturated NaCl solution or water. The assessment was performed by means of germination and health tests (freezing filter paper). The percentage of Aspergillus spp., Rhizopus sp. and Cladosporium sp. fungi, after incubation for the traditional aging test, was higher than the assessment made before the incubation, that did not occur when salt solution was used. The asepsis, when accomplished before the seed incubation, was efficient in minimizing the incidence of Aspergillus spp. The utilization of NaCl solution in substitution to water in the accelerated aging test inhibited the growth of Aspergillus spp., Rhizopus sp. and Cladosporium sp.

Magnolia ovata St. Hil. seed conservation

A pesquisa foi regularizada com o objetivo de estudar a influencia do teor de agua da semente e da temperatura de armazenamento sobre a conservacao das sementes de Magnolia ovata (Magnoliaceae), uma arvore nativa brasileira. Para tanto, sementes recem colhidas com 23,5% de agua foram submetidas a secagem para a obtencao de sementes com os teores de agua de 17,4%, 10,9% e 7,1%. Em seguida, as sementes foram acondicionadas em sacos de polietileno e armazenadas a 15oC e a 20oC. As sementes foram armazenadas por 180 dias e avaliadas mensalmente quanto ao teor de agua, a emergencia, ao indice e a velocidade de emergencia da plântula e ao comprimento e a massa da materia seca da plântula. A conservacao das sementes de Magnolia ovata e favorecida pela secagem das sementes; as condicoes favoraveis para a conservacao sao sementes com 10,9% de agua e 15oC ou 20oC de temperatura do ambiente de armazenamento.