Controle químico de doenças foliares na cultura do arroz irrigado

O objetivo deste trabalho foi avaliar a interferência das doenças foliares na produtividade de duas cultivares de arroz irrigado, bem como determinar a interação entre ingredientes ativos e momento de aplicação, para o controle de escaldadura e mancha-marrom. Foram utilizados: tiofanato metílico, tebuconazole, azoxystrobin e trifloxystrobin + propiconazole, aplicados em cinco épocas, às cultivares IRGA 417 e El Passo L 144. Os parâmetros avaliados foram: severidade das doenças e rendimento de grãos. O controle químico proporcionou redução significativa na severidade das doenças, em ambas as cultivares, com reflexo no rendimento de grãos, e foi influenciado pelo produto e pela época de aplicação.

Aplicação do silício para aumentar a resistência do arroz à mancha-parda

O objetivo deste trabalho foi avaliar fontes e métodos de aplicação de silício para aumentar sua absorção e a resistência de plantas de arroz (Oryza sativa), cultivar Metica-1, à mancha-parda (Bipolaris oryzae). Foram conduzidos dois experimentos em casa de vegetação, com solo Latossolo Vermelho. O delineamento experimental foi o completamente casualizado, com oito repetições. As fontes foram wollastonita (silicato de cálcio), aplicada via solo, e silicato de potássio e ácido monossilícico, aplicados via foliar. A aplicação de silício via solo resultou em aumento do teor foliar deste elemento e foi eficiente na indução de resistência à mancha-parda, diferentemente do observado com sua aplicação via foliar.

Genetic variation among pathogens causing "Helminthosporium" diseases of rice, maize and wheat

Twenty isolates of four fungal species, agents of "Helminthosporium" diseases in cereals, were collected from different regions: nine Bipolarisoryzae isolated from rice (Oryza sativa), seven B.sorokiniana from wheat (Triticum aestivum), two B. maydis, and two Exserohilumturcicum from maize (Zea mays). The strains were compared by PCR-RFLP and RAPD analysis. Size polymorphism among the isolates in the ITS region comprising the 5.8 S rDNA indicated genetic differences among the isolates, while a UPGMA phenogram constructed after the digestion of this region with restriction enzymes showed inter- and intra-specific polymorphism. The RAPD profiles indicated an expressive level of polymorphism among different species, compared with a low level of polymorphism among isolates of the same species. A UPGMA phenogram grouped the isolates according to the species and their host plant. RAPD profiles did not reveal polymorphism that directly correlated climatic factors with geographic source of the isolates of B. sorokiniana, and B. oryzae. Teleomorphic species revealed high similarity with their correspondent anamorphs.

Incidência de fungos e quantificação de danos em sementes de genótipos de arroz

O programa de melhoramento genético de arroz do Instituto Agronômico visa a obtenção de cultivares de arroz altamente produtivas, características tecnológicas desejáveis e resistência a doenças. O presente estudo avaliou genótipos de arroz integrantes dos ensaios comparativos avançados quanto à qualidade sanitária e severidade de manchas nas sementes, peso das sementes por panícula e esterilidade das espiguetas. A qualidade sanitária das sementes variou conforme o sistema de cultivo, com alta incidência dos fungos Pyricularia grisea, Bipolaris oryzae e Microdochium oryzae no cultivo inundado, enquanto que sob irrigação por aspersão predominaram Pyricularia grisea, Phoma sorghina e Drechslera spp. A severidade de manchas nas sementes apresentou correlação negativa com peso da panícula e número de grãos cheios, e positiva com número de grãos chochos e porcentagem de esterilidade. Destacaram-se em condições de cultivo irrigado por inundação as linhagens IAC 1817 e IAC 1818, apresentando os menores índices de severidade de manchas, e também baixas porcentagens de esterilidade e altos pesos de grãos por panícula. Em terras altas sob irrigação por aspersão, destacaram-se a linhagem IAC 1776 e a cv. Bonança, com os menores índices de severidade de manchas, e a linhagem 1781, com baixas incidências dos mais importantes patógenos, e também baixa esterilidade. Esses resultados serviram como indicadores do nível de resistência e/ou tolerância dos genótipos a manchas de grãos.

Influência da embalagem e do armazenamento na qualidade sanitária de sementes de arroz

O presente trabalho foi conduzido no Laboratório de Patologia de Sementes do Centro de Fitossanidade (área de Fitopatologia) do Instituto Agronômico de Campinas (IAC), tendo como objetivo avaliar a qualidade sanitária de sementes de arroz, em dois tipos de embalagem (sacos de papel multifoliado e de plástico trançado), durante 12 meses de armazenamento (junho de 1996 a junho de 1997), em condições de ambiente natural de Campinas, SP. As sementes foram avaliadas no início e a cada dois meses. O experimento foi analisado estatísticamente pelo delineamento inteiramente casualizado, em parcelas subdivididas no tempo, com quatro repetições. Os principais fungos detectados nos lotes de sementes de arroz foram: Pyricularia grisea, Bipolaris oryzae, Fusarium spp., Phoma spp., em pequenas porcentagens Curvularia spp., Cladosporium spp., Alternaria spp. e os fungos de armazenamento Penicillium spp. e Aspergillus spp. Durante o período de armazenamento, não houve diferença significativa na sanidade das sementes para as embalagens de papel multifoliado e plástico trançado. A incidência dos fungos Penicillium spp. e Aspergillus spp., aumentou durante o armazenamento.As sementes de arroz apresentaram boa armazenabilidade nas condições de Campinas, SP, devido a baixa umidade relativa do ar e o clima seco.

Fungi associated with foliar diseases of wild and cultivated rice (Oryza spp.) in northern Queensland

During surveys of wild and cultivated rice in northern Queensland in 2014 and 2015, 92 fungal isolates were obtained from plants that were afflicted by foliar diseases, including the rice blast pathogen, Pyricularia oryzae, and the brown spot pathogen, Bipolaris oryzae. Seven species of Curvularia were found, viz. Curvularia aeria, C. alcornii, C. asianensis, C. clavata, C. lunata, C. muehlenbeckiae and an undescribed species. To remove uncertainty about the identity of the host plants from which the fungi were isolated, a DNA barcoding strategy was developed using regions of the chloroplast genome. Pathogenicity tests using wild rice isolates of P. oryzae indicated that many local rice varieties are susceptible to infection.

Enzymatic Biodiesel Synthesis From Yeast Oil Using Immobilized Recombinant Rhizopus Oryzae Lipase.

The recombinant Rhizopus oryzae lipase (1-3 positional selective), immobilized on Relizyme OD403, has been applied to the production of biodiesel using single cell oil from Candida sp. LEB-M3 growing on glycerol from biodiesel process. The composition of microbial oil is quite similar in terms of saponifiable lipids than olive oil, although with a higher amount of saturated fatty acids. The reaction was carried out in a solvent system, and n-hexane showed the best performance in terms of yield and easy recovery. The strategy selected for acyl acceptor addition was a stepwise methanol addition using crude and neutralized single cell oil, olive oil and oleic acid as substrates. A FAMEs yield of 40.6% was obtained with microbial oils lower than olive oil 54.3%. Finally in terms of stability, only a lost about 30% after 6 reutilizations were achieved.

Optimization of the Enzymatic Interesterification of Milk Fat and Canola Oil Blends Using Immobilized Rhizopus oryzae Lipase by Response Surface Methodology

Blends of milk fat and canola oil (MF:CNO) were enzymatically interesterified (EIE) by Rhizopus oryzne lipase immobilized on polysiloxane-polyvinyl alcohol (SiO(2)-PVA) composite, in a solvent-free system. A central composite design (CCD) was used to optimize the reaction, considering the effects of different mass fractions of binary blends of MF:CNO (50:50, 65:35 and 80:20) and temperatures (45, 55 and 65 degrees C) on the composition and texture properties of the interesterified products, taking the interesterification degree (ID) and consistency (at 10 degrees C) as response variables. For the ID variable both mass fraction of milk fat in the blend and temperature were found to be significant, while for the consistency only mass fraction of milk fat was significant. Empiric models for ID and consistency were obtained that allowed establishing the best interesterification conditions: blend with 65 % of milk fat and 35 %, of canola oil, and temperature of 45 degrees C. Under these conditions, the ID was 19.77 %) and the consistency at 10 degrees C was 56 290 Pa. The potential of this eco-friendly process demonstrated that a product could be obtained with the desirable milk fat flavour and better spreadability under refrigerated conditions.

Interesterification of milkfat with soybean oil catalysed by Rhizopus oryzae lipase immobilised on SiO(2)-PVA on packed bed reactor

The potential of the lipase from Rhizopus oryzae immobilised on SiO(2)-PVA to catalyse the interesterification of the milkfat with soybean oil in a packed bed reactor running on continuous mode was evaluated. The reactor operated continuously for 35 days at 45 degrees C, and during 12 days, no significant decrease in the initial lipase activity was verified. Interesterification yields were in the range from 35 to 38% wt, which gave an interesterified product having 59% lower consistency in relation to non-interesterified blend. Results showed the potential of the lipase from Rhizopus oryzae to mediate the interesterification of milkfat with soybean oil in packed bed reactor, attaining a more spreadable product under a cool temperature. The biocatalyst operational stability was assessed and an inactivation profile was found to follow the Arrhenius model, revealing values of 34 days and 0.034 day(-1), for half-life and a deactivation coefficient, respectively.

Interesterification of milkfat and soybean oil blends catalyzed by immobilized Rhizopus oryzae lipase

Milkfat (MF)/soybean oil (SBO) blends ranging from 50% to 100% of milkfat (w/w) were enzymatically interesterified with a sn-1,3 specific lipase from Rhizopus oryzae immobilized on polysiloxane-polyvinyl alcohol matrix, in a solvent free medium. Interesterification progress was monitored by following the changes in the relative proportions of 50-carbon triacylglycerols (TAGS) to 44-carbon TAGs (50/44 ratio) in the reaction. The starting materials and products were also analyzed in terms of consistency measured in a texturometer. All reactions gave interesterified (IE) products with lower consistency than non-interesterified (NIE) MF:SBO blends and interesterification degree varied from 0.54 to 2.60 in 48 h reaction. The highest interesterification degree was achieved for 65:35 MF:SBO blends, which gave 76% reduction in the consistency. These results showed the potential of the immobilized lipase to change the TAGs profile of the MF:SBO blend allowing to obtain cold-spreadable milkfat. (C) 2010 Elsevier B.V. All rights reserved.

Subcutaneous mucormycosis caused by Rhizopus oryzae: probable nosocomial acquired infection

The Authors present a case of subcutaneous mucormycosis occurring in a patient with clinical and biochemical evidence of diabetic ketoacidosis. The clinical, mycological and histopathological features are described, emphasizing the relevance of a rapid diagnosis in order to stablish early treatment. The clinical forms of mucormycosis and the main associated conditions are briefly reviewed as well as the most probable conditions which may lead to the enhanced susceptibility to infection in the diabetic patient in ketoacidosis. The recovery of Rhizopus oryzae from the air of the room of the patient suggests a nosocomial infection acquired through contamination of venous puncture site by air borne spores.

Subcutaneous phaeohyphomycosis caused by Bipolaris hawaiiensis: a case report

A case of phaeohyphomycosis caused by Bipolaris hawaiiensis is reported. The patient, an immunocompetent host, presented a verrucous lesion on the first finger of the left foot. Dematiaceous septate hyphae and yeast-like elements were seen in direct and histological examination. The isolated strain was identified on the basis of micro and macromorphological aspects. Treated with electrocoagulation, the lesions healed and presented no relapse after two years follow-up.

Potencial fungitóxico do óleo essencial de Piper hispidinervum (pimenta longa) sobre os fungos fitopatogênicos Bipolaris sorokiniana, Fusarium oxysporum e Colletotrichum gloeosporioides

O objetivo deste trabalho foi avaliar a atividade fungicida in vitro do óleo essencial das folhas de Piper hispidinervum sobre Bipolaris sorokiniana, Fusarium oxysporum e Colletotrichum gloeosporioides. Para os ensaios biológicos, empregou-se o teste bioanalítico in vitro utilizando as concentrações de 100, 200, 500, 1000, 1500 e 2000 µg.mL-1 do óleo essencial. Estas foram incorporadas no meio de cultura BDA (batata-dextrose-ágar) para avaliação do crescimento ou inibição micelial. O delineamento estatístico utilizado foi o inteiramente casualizado, com quatro repetições. Na concentração de 200 µg.mL-1, observou-se uma inibição total do fitopatógeno Bipolaris sorokiniana enquanto que, para o Fusarium oxysporum e o Colletotrichum gloeosporioides esta ocorreu na concentração de 1000 µg.mL-1.

On the morphological "variation" on the aedaegus of Schizotetranychus oryzae (acari, prostigmata, tetranychidae)

Sobre a "variação" morfológica do edéago de Schizotetranychus oryzae (Acari, Prostigmata, Tetranychidae). Apresenta-se uma nota sobre a ocorrência do ácaro do arroz, Schizotetranychus oryzac Rossi de Simons, No Brasil, com observações sobre a "variação" morfológica do edéago do macho desta espécie de ácaro.

Toxic effects of essential plant oils in adult Sitophilus oryzae (Linnaeus) (Coleoptera, Curculionidae)

Toxic effects of essential plant oils in adult Sitophilus oryzae (Linnaeus) (Coleoptera, Curculionidae). Stored grains are subject to losses in quality nutritional value and in sanitation from the time they are stored to the time they are consumed. Botanical insecticides may offer an alternative solution for pest control. The objective was to test the insecticidal properties of the essential oils of Cymbopogon citratus (leaf), Zingiber officinale (root) and Mentha sp. (leaf). The efficacy of these oils was tested to control the rice weevil, S. oryzae, using hydrodistillation. Chemical analysis of the essential oils was carried out by gas chromatography. Major components of C. citratus were geranial (48%) and neral (31%), of Z. officinale were α-zingibereno (13%), geranial (16%), neral (10%) and α-farneseno (5%) and of Mentha sp. was menthol (92%). Bioassays were carried out by fumigation and topical application. In topical application assays, the essential oil of C. citratus had greater toxicity (LC50 0.027 µL mL-1) and shorter exposure time than the oils of the other two plants. After 24 h and 48 h, 70% and 100% mortality of S. oryzae occurred, respectively. In fumigation assays, essential oil of Z. officinale had a lower LC50 (1.18 µL cm-2) and 70% mortality after 24 h exposure. Therefore, we recommend the use of essential oils of C. citratus and Z. officinale to control the rice weevil S. oryzae.