Sérgio Miguel Mazaro

Comportamento pós-colheita de frutos de morangueiro após a aplicação pré-colheita de quitosana e acibenzolar-S-metil

ABSTRACT - The use of inductors of resistance in plants represents an alternative and a promising method to control fruit rots at postharvest. The experiment was carried out at Federal Technological University of Parana - Dois Vizinhos - Campus, during 2004 wit h theobjective to evaluate the induction of chitosan resistance and acibenzolar-S-methyl (ASM) on strawberry plants. The treatmentscompared the effect of chitosan (0.5; 1.0 and 2.0%) and ASM (0.0025%) in relation to control plants (distilled water only) and those withfungicides application. The chitosan treatment in all three evaluated concentrations, delayed the fruit maturation, increased the fleshfirmness and titratable acidity and decreased the mass loss. It was also observed reduction in the ethylene production and in thereduced sugars and increased the total polyphenol in strawberry fruits. The chitosan treatment in all three evaluated concentrationsinduced greater plant resistance to diseases with effect on the reduction of the fruit rots in the post harvest by Botrytis cindered.Although, chitosan treatment in the concentration of 2% caused damage to the fruits in the post harvest increased the respiration rateand the reduced sugar. The ASM had effect on the retention of the titratable acidity and acted efficiently on the rot reduction similar tothe treatment with fungicides. The application of chitosan and ASM pre-harvest did not interfere in the organoleptic quality of the fruitsin the post harvestIndex Terms: elicitor, ASM, chitosan, strawberry, quality, Botrytis cinerea.

Influência do uso de AIB, época de coleta e tamanho de estaca na propagação vegetativa de hibisco por estaquia

Effects of IBA concentration, collection time and cutting length on hibiscus cutting propagation Vegetative propagation by tip cutting can be influenced by factors such as collection time, cutting length, auxin concentration and cutting physiological status. The ornamental Hibiscus ( Hibiscus sp.) is commercially propagated by cuttings. Therefore, there is a need to study the influence of these factors on the rooting capacity of this specie. The aim of this work was to evaluate the IBA effect, cutting length and collection time on Hibiscus tip cutting propagation. The experiment was carried out in the plant production sector of the Universidade Tecnologica Federal do Parana, Campus Dois Vizinhos, Dois Vizinhos, PR (Brazil). The experiment was arranged in a 3 x 2 x 2 factorial completely randomized block, (IBA concentration x cutting length x collection time), with four replications, with each plot consisting of ten cuts. Two collecttion times (June and September), two shoot cutting lengths (6 and 12 cm) and three IBA concentrations (0; 1 and 2 g L -1 ) were tested. At the two collection times, after 77 days, the rooting percentage, number

Indução de fitoalexinas em cotilédones de soja em resposta a derivados de folhas de pitangueira

The worldwide demand for food without pesticides has stimulated the research on alternative methods to control pathogens in plants. The activation of defense mechanisms by inductors seems a viable and promising alternative. The use of medicinal plants extracts has demonstrated capacity to induce the production of phytoalexins, as a mechanism of defense in treated plants. The objective of this research was to verify the potential of Eugenia uniflora L. (surinan cherry) to induce phytoalexins in cotyledons of soybean (Glycine max). The derivatives alcoholic extract, infusion, maceration and decoction, obtained of surinan cherry were used in the concentrations of 0.1; 1; 10 and 40%, beyond essential oil. Water was used for the control and chitosan (1%) as inductor reference. The preparations of surinan cherry presented capacity of induction of the phytoalexins glyceolin in cotyledons of soybean, with the increasing concentration of the preparations. The essential oil presents detachable effect in the induction of phytoalexins in relation to the other preparations. Chitosan induces phytoalexins in cotyledons soybean and can be used in similar studies as a reference inductor.

Variability in leaf rust susceptibility among peach cultivars

The aim of this work was to estimate the susceptibility of thirty-six peach cultivars to leaf rust caused by Tranzschelia discolor f. sp. persica. The incidence and severity of the disease as well as defoliation in peach trees of an experimental orchard of Parana Federal University of Technology, Campus Dois Vizinhos were evaluated on the growing seasons 2004/2005 and 2005/2006. Immunity to this disease was not observed in the studied cultivars. There was difference in leaf rust intensity depending on the growing season conditions. Cultivars ‘Pilcha‘, ‘Sinuelo‘, ‘Chirua‘, ‘Sulina‘, ‘Eldorado‘ and ‘Pampeano‘ showed tolerance to leaf rust, whereas cultivars ‘Vila Nova‘, ‘Fla 1372‘, ‘Coral 2‘, ‘Chimarrita‘, ‘Della Nona‘, ‘BR-1‘ and ‘Guaiaca‘ showed high susceptibility.

A quitosana como fungistático no crescimento micelial de Rhizoctonia solani Kuhn

Rhizoctonia solani is a fungus that causes damping-off of seedlings in various plant species. Chitosan is a polymer derived from the process of desacetylation of chitin, which is found in large quantities in the exoskeleton of crustaceans, insects and fungal cell wall. Chitosan has been tested for various uses, including the control of plant pathogens in agriculture, since it presents antimicrobial activity to control pathogens. This study aimed to evaluate the fungistatic effect of different chitosan concentrations (0; 0.25; 0.5; 1 and 2%) in mycelial growth in vitro of the fungus R. solani. The results showed a significant effect of different concentrations of chitosan, in reduccing the mycelial growth of R. solani. It was also observed increased fungistatic effect with increasing of the concentration.

Associação e densidade populacional de ácaros predadores em plantas de erva-mate Ilex paraguariensis St. Hil. (Aqüifoliaceae) na presença ou na ausência de ácaros fitófagos

This research was aimed at evaluating the association and concentration of predators mites in the mate-tea tree Ilex paraguariensis St. Hil. (Aquifoliaceae) with or without phytophagous mites. This study was conduced at Dois Vizinhos, State of Parana, from August 2001 to July 2002, in a mate-tea tree commercial plantation. Leaf samples from different parts of the plant were taken monthly, and the number of mites was counted in laboratory. Two species of phytophagous mites, Dichopelmus notus Keifer and Oligonychus yothersi (McGregor), and three species of predator mites Euseius concordis (Chant), Iphiseiodes zuluagai Denmark & Muma, and Agistemus sp. were related to the mate-tea plant. The association of E. concordis and I. zuluagai to the leaves with D. notus, the association of Agistemus sp. to the plants with D. notus and a higher population density of E. concordis and I. zuluagai in plant with D. notus were observed.

Controle de doenças foliares e de flores e qualidade pós-colheita do morangueiro tratado com Saccharomyces cerevisiae

The effect of Saccharomyces cerevisiae was evaluated on the development of strawberry diseases and postharvest quality of fruits. The research was carried out in 2004 and 2005 in Parana State, Brazil. Five different preparations of the yeast S. cerevisiae (a suspension of commercial fresh biological yeast for bakery, a suspension of yeast cells, a suspension of autoclaved cells, a filtered yeast liquid culture and the commercial product Agro-MOS®) were compared to control treatments (distilled water spraying and another one with fungicides). None of the preparations were effective against the mycosphaerella leaf spot (Mycosphaerella fragariae); preparations with living cells and the product Agro-MOS® showed effect against leaf blight (Dendrophoma obscurans); suspension of the bakery yeast and the filtered liquid culture reduced the incidence of anthracnose (Colletotrichum acutatum) in flowers and fruits. Preparations of S. cerevisiae with suspension of cells, suspension of autoclaved cells and filtered liquid culture increased the productivity of the strawberry plants, which ranged from 589.6 to 617.8 g plant-1. The preparations of S. cerevisiae, with living cells or not, modified the plant metabolism, improving the activity of the chitinase and glucanase enzymes, which are involved in the acquired systemic resistance. Except for the treatment with suspension of autoclaved cells, the other preparations reduced the incidence of gray mould (Botrytis cinerea) in the postharvest of fruits.

Escala diagramática para avaliação da severidade da mancha-de-dendrophoma em morangueiro

A diagramatic scale was developed and validated to assess dendrophoma severity in strawberry, caused by Dendrophoma obscurans (Ell E 2.9; 9.1; 25.2; 53.3 and 79.5%. Assessments with the diagrammatic scale were of great precision and higher accuracy for all appraisers. The proposed diagrammatic scale was considered adequate to estimate dendrophoma blight severity in strawberry and will be used in epidemiological studies and in the evaluation of control strategies for this disease.

Chilling requirement for seed germination and phenological observations on peach cultivars

In subtropical climate areas, the models and methods proposed to evaluate the chilling requirement of temperate fruit crops often do not provide satisfactory results, thus calling for the development of alternative techniques. The aim of this study was to evaluate the correlations between some phonological traits and chilling requirement for seed germination of 18 peach cultivars and one nectarine cultivar . Two experiments were installed separately for the correlation studies. In experiment 1, the phenological traits were observed in the field, while in experiment 2, the chilling requirement for 50 and 100% seed germination of each cultivar was assessed. The number of days for beginning of bloom (r = 0.70**, 0.61**) and full bloom (r = 0.72**, 0.76**) were both significantly correlated with the number of chilling units for 50% and 100% germination of seeds. The number of days for beginning of budding and dormancy break were both significantly correlated with the number of chilling units for 50% and 100% germination (r = 0.48*, 0.50*, respectively). However, the same significant effect for these phenological traits was not found between chilling units and 50% germination of seeds, as well as between chilling units and harvest dates.

Eficiência de Beauveria bassiana Vuill. e Isaria sp. para o controle de Thaumastocoris peregrinus Carpintero & Dellapé (Hemiptera: Thaumastocoridae).

The search for information to control Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae) in Eucalyptus , focus on the use of biological control techniques, including the use of entomopathogenic fungi. The objective of this study was evaluated the pathogenicity of Beauveria bassiana and Isaria sp. on Thaumastocoris peregrinus, under laboratory conditions. To do so, we tested four isolates of Beauveria bassiana and one isolate of Isaria sp. concentration of 1.0 × 10 8 conidia mL -1 . The solution was applied on leaves of Eucalyptus camaldulensis , provided as food for the insect substrates, and maintained in glass bottles sealed with plastic film in a climatic chamber (26 ± 2 ° C, 14 h photoperiod and U.R. 70 ± 10%). Four replicates were performed (bottles) for isolated with 13 adult insects per bottle. Each bottle received 13 adult insects. Evaluations were performed until the fifth day after application. The dead insects were placed in humid chamber for confirmation of death by pathogen. All isolates were pathogenic to Thaumastocoris peregrinus . The confirmed mortality ranged between 37% and 80.1% for Beauveria bassiana , and was 87% for Isaria sp. after 10 days of application. The highest mean percentage of daily mortality (39.9%) occurred on the fourth day after contact with the substrate insect spray. The isolates of Beauveria bassiana and Isaria sp. evaluated presented potential to control Thaumastocoris peregrinus under laboratory conditions.