Reginaldo Gonçalves Mafia

Microbiolization and interaction between growth promoting rhizobacteria and eucalyptus clones

This work aimed to evaluate methods of microbiolization and interaction between isolates of rhizobacteria and eucalyptus clones. W e have tested the following methods of micr obiolization: a) Addition of suspension of rhizobacteria (10 8 cfu/mL) to the substrate (0.2 mL/cc); b) Immersion of mini-cuttings in the inoculum suspension (10 8 cfu/mL); and c) Combination of the two methods (a and b). Mini-cuttings of a hybrid clone of eucalyptus (Eucalyptus grandis x Eucalyptus urophylla) and three (3918, FL2 and S1) rhizobacteria isolates were used. Twenty-five days after the mini-cuttings wer e planted, the rooting, root biomass and disease incidence were evaluated. In general, there were no significant differences between the microbiolization methods. All rhizobacterial isolates increased rooting, biomass and biocontrol of Cylindrocladium spp. In another experiment, the results showed interaction between eucalyptus clones and rhizobacteria isolates for the rooting index and root biomass.

Primeiro registro de Chalcodermus bicolor (Coleoptera: Curculionidae) em plantios de eucalipto

This research aimed to record, for the first time, the damage caused by a pruner beetle on hybrid eucalypts cloned trees (Eucalyptus urophylla vs. E. grandis), located in Bahia and Espirito Santo States, Brazil. The specie was determined as Chalcodermus bicolor Fiedler, 1936 (Curculionidae: Molytinae). The female prunes the tree shoot and lays a single egg inside a small hole, just below the incision point. Eucalypt is the first host recorded to this pruner beetle specie.

Método de seleção e identificação de fontes de resistência à murcha do eucalipto causada por Ceratocystis fimbriata

The objective of this work was to develop a screening method and to identify resistance source to eucalyptus wilt caused by Ceratocystis fimbriata. The inoculation of 5 ml of pathogen inoculum (2.5 × 104 spores/ml) on the wound root crown of seedlings at 60 days of age was the most efficient method to reproduce the disease symptoms. For this method, disease severity and plant mortality in function of time after inoculation were assessed. A 30-day period after inoculation was sufficient to reproduce disease symptoms. The developed inoculation protocol showed high performance (400 plants/h), and less space consume, when compared with other methods, mainly because it enables the inoculation of young eucalyptus seedlings (60-90 days of age). In the second phase of this work, it was evaluated the eucalyptus inter-specific resistance to C. fimbriata by using the species: Eucalyptus camaldulensis, E. dunnii, E. grandis, E. pellita, E. saligna, E. tereticornis and E. urophylla. There was resistance segregation for all species and according to the origin place of the population. For E. urophylla, for example, occurred the greatest variations among the number of resistant individuals and susceptible to diseases. Those variations can be linked to seed precedence and to genetic improvement program characteristics.

Eucalypt plants are physiologically and metabolically affected by infection with Ceratocystis fimbriata

Ceratocystis wilt, caused by Ceratocystis fimbriata, is currently one of the most important disease in eucalypt plantations. Plants infected by C. fimbriata have lower volumetric growth, lower pulp yields and reduced timber values. The physiological bases of infection induced by this pathogen in eucalypt plant are not known. Therefore, this study aims to assess the physiological and metabolic changes in eucalypt clones that are resistant and susceptible to C. fimbriata. Once, we evaluated in detail their leaf gas exchange, chlorophyll a fluorescence, water potential, metabolite profiling and growth-related parameters. When inoculated, the susceptible clone displayed reduced water potential, CO2 assimilation rate, stomatal conductance, transpiration rate, photochemical quenching coefficient, electron transport rate, and root biomass. Inoculated resistant and susceptible clones both presented higher respiration rates than healthy plants. Many compounds of primary and secondary metabolism were significantly altered after fungal infection in both clones. These results suggest that, C. fimbriata interferes in the primary and secondary metabolism of plants that may be linked to the induction of defense mechanisms and that, due to water restrictions caused by the fungus in susceptible plants, there is a partial closure of the stomata to prevent water loss and a consequent reduction in photosynthesis and the transpiration rate, which in turn, leads to a decrease in the plants growth-related. These results combined, allowed for a better understanding of the physiological and metabolic changes following the infectious process of C. fimbriata, which limit eucalypt plant growth.

INTENSIDADE DE QUEIMA DE DIFERENTES RETARDANTES DE FOGO

This research aimed to evaluate the effect of different types of fire retardants and dosages in the efficiency of fighting forest fires. The experiment was conducted in combustion table in the laboratory with 4 types of flame retardants (WD 881, RFC-88, F-500 and HMIS 1-0-0 DPnB) at 3 concentrations (0.5%, 1% and 1.5%) plus water as control. The dosage of the tail of the retardant mixture with water was 0.5 liter per square meter of area. For the analysis it was measured the time that it took to the fire to consume the area with the application of the product and the distance between the top of the parcel and the location where the fire was extinguished. During the firing of each plot (treatment / repeat) the following variables were evaluated: relative humidity, wind speed, time spent by the fire to burn the plot with and without the product and the distance advanced by the fire in the parcel with the product. Retardants with greater efficiency were F-500, HMIS 1-0-0 DPnB and WD 881, that showed significant differences by Tukey test at 5% probability, differentiating the control and the RFC-88. The most effective concentration was 1.5% with the lowest levels of flammability in all cases.

Mapeamento de áreas de risco para ocorrência da ferrugem do eucalipto no Espírito Santo e extremo sul da Bahia

Eucalyptus rust caused by Puccinia psidii Winter, is one of the most important diseases of Eucalyptus. The pathogen causes disease mainly in leaves, stems and young shoots, under conditions of leaf wetness up to 6 hours for 5 to 7 consecutive days and temperatures from 18 to 25 o C, with optimum 23 o C. Considering the influence of climatic conditions in the life cycle of the pathogen, the planting of eucalyptus in times and places unfavorable to the occurrence and development of the pathogen is one of the possible strategies for integrated disease management. This study aimed to map risk areas for the occurrence of eucalyptus rust in the Espirito Santo and southern Bahia. Therefore, was calculated the rate of infection (II) from the average daily maximum temperature (T) and duration of leaf wetness (H) as the model II = -32.263 + 3.699 T + 0.461 H - TH 0.0018 - 0.0903 T2 - 0.0068 H2. The data used were obtained from the meteorological database, of the Regiao Aracruz and Sao Mateus (Espirito Santo) and Regiao Teixeira de Freitas (Bahia) for the years 2001 to 2006, a total of 26 weather stations. From the rate of infection was carried out to calculate a correction factor, defined as the ratio between the value 100 and the highest interpolated value of infection rate, to classify the values within a range from 0 to 100 points risk, generating the risk index. Based on the value of risk index, drawn up maps of spatial and temporal distribution of disease occurrence, using the software ArcGIS 9.2 TM. According to the results it is concluded that the months from May to November are the most favorable for the occurrence of the disease. The adopted methodology was efficient for the mapping of the risk of eucalyptus rust, considering the spatial and temporal distribution.

Avaliação da resistência do eucalipto à murcha-bacteriana causada por Ralstonia solanacearum

The use of resistant eucalyptus clones is the most important strategy to disease control on the field. Thus, this work aimed to evaluated methods of Ralstonia solanacearum inoculation in order to select eucalyptus resistant to bacterial wilt. The inoculation methods were selected due to ease of operation and tested in order to evaluate four clones (hybrids E. urophylla x E. grandis): i) application of 5 mL pathogen inoculum (108 cfu/mL) on the root collar of seedlings; ii) application of 5 mL of pathogen inoculum (108 cfu/mL) on the root collar of seedlings after wound of the radicular system; iii) cut of 1/3 basal of the radicular system and immersion of the roots into pathogen inoculum, at the same concentration, for 1 min; and iv) conduction of seedlings transplanted to infested sand maintained in container with application at 15 days intervals (rate of 0.25 L/m3) and bacterial suspension (108 cfu/mL) and submitted to collection of sprouting, similarly as it is done in commercial clonal mini-garden. The seedlings transplant to infected sand presented a higher incidence of the disease (bacterial exudation), ranging from 81 to 100%. The second trial aimed to evaluate resistance of different eucalyptus species, using the method of transplanting seedlings to the infected sand. The evaluation of the infection by exudation bacterial method was more appropriate to compare the genotypes. The bacterial wilt intensity was affected by plant and environment conditions. Every species showed disease symptoms, but E. tereticornis and E. grandis showed, respectively, the lowest (33.3%) and the highest (91.7%) percentage of infected genotypes (susceptible). The results of this work are important tools (inoculation method) and resistance sources (eucalyptus species) to bacterial wilt disease control in eucalyptus.

Análise comparativa dos surtos e danos causados pelos besouros desfolhadores Costalimaita ferruginea (Fabricius, 1801) e Costalimaita lurida (Lefévre, 1891) (Coleoptera: Chrysomelidae) em plantios de eucalipto

The leaf beetles Costalimaita ferruginea (Fabricius, 1801) and Costalimaita lurida (Lefevre, 1891) (Coleoptera: Chrysomelidae) are important eucalyptus pests. The biology aspects and pest behavior of C. ferruginea have already been characterized by previous works, but there are no studies about C. lurida potential to cause damage to eucalyptus yield. This work evaluated and compared the pest outbreaks and injuries caused by C. ferruginea and C. lurida to young eucalypt plantations. We have monitored 202.8 thousand hectares of clonal eucalypt plantations in Espirito Santo, Bahia and Minas Gerais states in Brazil during the critical period of pest occurrence (warmest and rainiest seasons). The pest peaks were characterized by the measuring of samples regarding the pest occurrence, the severity of attack and the absolute and relative population of insects per attacked plant. In general, C. lurida pest behavior was similar to C. ferruginea regarding the period of occurrence and injuries patterns. However, C. lurida has shown heavier infestations considering absolute peaks (insects per plant), relative outbreaks (ratio between number of insects and plant height) and was also distributed in a bigger area, thus causing more damage than C. ferruginea. The beetle C. lurida should be monitored in the same way and making use of the same criteria and control premises developed to C. ferruginea. Additionally to the obtained results, this work recorded for the first time the occurrence of C. lurida in Bahia State and damages caused by this insect on wild guava plants of Psidium guineense Swartz (Myrtaceae).

Caracterização dos danos causados por Heilipodus naevulus em plantios de eucalipto no Espírito Santo, Brasil

This research aimed to evaluate the effects of damages caused by Heilipodus naevulus Mann. (Coleoptera: Curculionidae) to the development of eucalyptus young plantation, and to record, for the first time, the occurrence on Espirito Santo State, Brazil. The critical period of occurrence was observed between October to December according with rain regime. The damages caused by the pest reduced the development and quality of eucalyptus trees.

Procedimento estatístico para validação de escalas diagramáticas na quantificação de doenças

RESUMO – Na validacao de escalas diagramaticas de doencas e comum utilizar a regressao linear simples para testar a identidade entre dados estimados e valores reais de severidade de doenca. Nestes casos, apos ajustar a regressao linear, as hipoteses H01: β 0 = 0 e H02: β 1 = 1 ao testadas, mas nao de forma simultânea, ou seja, se β 0 = 0 ao mesmo tempo em que β 1 = 1, ou, se β 1 = 1 ao mesmo tempo em que β 0 = 0. O objetivo deste trabalho foi propor um novo procedimento estatistico para validacao de escalas diagramaticas, denominado L&O. Este procedimento resulta da combinacao do teste F, modificado por Graybill (1976), teste t para o erro medio e analises do coeficiente de correlacao linear. Este procedimento foi aplicado para testar a identidade entre valores estimados e valores reais de severidade da doenca causada por Quambalaria eucalypti em eucalipto. Os resultados mostraram que o procedimento estatistico foi eficiente, nao subjetivo e permitiu tambem testar a identidade entre quaisquer dois vetores ou grupos de dados quantitativos.