Strong population subdivision according to the host was revealed in a study designed to assess the genetic variability of Alternaria solani on potato (Solanum tuberosum) and tomato (S. lycopersicum) in Brazil (Lourenço Jr. et al., 2009).We hypothesised that more than one species cause early blight disease on these hosts. We analysed 19 isolates obtained from potato and nine from tomato, sampled from 2005 to 2008 from seven geographic regions. Ex-type and authentic isolates of A. tomatophila , and a representative isolate of were used for comparison (Simmons, 2000). Based on morphological characteristics all isolates from tomato were identified as A. tomatophila and those from potato as A. grandis (Simmons, 2007) (Fig. 1; Table 1).A. solani was not detected in the samples. A preliminary report has been previously published (Rodrigues & Mizubuti, 2009).The pathogenicity of three isolates from tomato and five from potato were tested on susceptible plants in cross inoculation assays. Two drops of a 10 4 conidia/ml suspension were placed on five leaflets in each plant (six plants/isolate). The lesion diameter (mm) was determined using a digital caliper and the formula of the area of a circle was used to estimate the lesion area (LA) four days after inoculation. On potato, the mean LA for A. grandis was 464.1 (SD = 53.0) compared to 345.9 (SD = 48.0) for A. tomatophila. On tomato, the mean LA for A. tomatophila was 64.9 (SD = 5.2) compared to 33.8 (SD = 8.1) for A. grandis. Although larger lesions were formed when A. grandis and A. tomatophila were inoculated on their host of origin, there was no statistical difference between species on a particular host. The isolates were recovered from the lesions to fulfil Koch's Postulates. Additionally, reconstruction of the phylogeny was used to investigate the relationships among the species. The major allergen Alt a1 and glyceraldehyde-3-phosphate (Gpd) genes data set were analysed. The Brazilian isolates from tomato clustered with the ex-type A.tomatophila isolate with strong support from parsimony (MP) and neighbour-joining (NJ) analyses. The A. grandis population clustered most closely with the ex-type isolate of A. grandis in a clade also including A. solani (Fig. 2). Alternaria tomatophila has been recorded to cause early blight on tomato in the United States, Australia, New Zealand, and Venezuela (Simmons, 2000).In Brazil, A. solani has been reported as the causal agent of early blight (Lourenço Jr. et al., 2009). We report here that at least two additional species are widely distributed on tomato and potato fields in Brazil.

Utilizando tamanho de pústulas e número de soros como critérios para avaliar a severidade, estabeleceu-se a seguinte escala de notas para quantificação da ferrugem causada por Puccinia psidii em mudas inoculadas de Eucalyptus sp.: S0 = imunidade ou reação de hipersensibilidade, com necrose ou "fleck"; S1 = pústulas puntiformes, < 0,8 mm de diâmetro; S2 = pústulas medianas, de 0,8 a 1,6 mm de diâmetro; e S3 = pústulas grandes, > 1,6 mm de diâmetro. Aferiu-se essa escala mediante o uso do marcador RAPD AT9/917, geneticamente ligado a um gene de resistência à ferrugem, em uma progênie de E. grandis. Apenas as plantas das classes S0 e S1 apresentaram o referido marcador e foram consideradas resistentes. A inconsistência na classificação de plantas resistentes e suscetíveis foi baixa (8%). O uso dessa escala permitiu a seleção de grande número de plantas resistentes à ferrugem com relativa rapidez, facilidade e precisão.Palavras-chave adicionais: severidade, avaliação da resistência, Puccinia psidii. ABSTRACT Rating scale to eucalypts rust severity evaluationBased on the pustule size, a rating scale was developed for evaluation of rust severity in inoculated seedlings of Eucalyptus sp. as follow: S0 = immunity or hypersensitive reaction, with necrosis or fleck; S1 = small pustules, < 0.8 mm diameter; S2 = medium sized pustules, from 0.8 to 1.6 mm diameter and S3 = large pustules, > 1.6 mm diameter.This scale was checked in a segregant progeny of E. grandis by using the RAPD AT9/917 marker, tightly linked to a rust resistance locus. Only plants classified as S0 and S1 had the RAPD marker and were considered resistant. The error in the classification of resistant and susceptible plants was low (8%). The use of this scale allowed a very fast and accurate screening of rust resistant genotypes.

Botrytis blight, caused by Botrytis cinerea (Bc), is an important disease on roses grown in plastic greenhouses in Brazil. Biocontrol with Clonostachys rosea (Cr) applied to leaves and crop debris to reduce pathogen sporulation can complement other control measures for disease management. Two experiments, each with a rose cultivar, were conducted in a plastic greenhouse. For ÔRed Success,Õ four treatments were compared: (1) control; (2) fortnightly sprays of Cr; (3) weekly sprays of mancozeb; and (4) weekly sprays of either Cr or mancozeb to the lower third of the plants and the debris. For ÔSonia,Õ treatment 4 was not included. Samples were taken from debris (leaves and petals) at ten 15-day intervals and plated on PCA medium. Sporulation of fungi and incidence of Botrytis blight on buds were assessed. For both cultivars, C treatments significantly (P ¼ 0:05) reduced Bc sporulation. However, disease incidence was not consistently reduced, probably because the applications of C. rosea started when Botrytis blight epidemic was advanced and no sanitation practices were performed on nontreated plots. From the present and previous studies, continuous application of Cr on debris, associated with sanitation practices, has the potential to reduce Bc sporulation and disease incidence in the buds.

The pattern of Cylindrocladium pteridis adhesion, germination and penetration in eucalypt leaves was assessed using scanning electron microscopy. The effects of inoculum concentration, leaf wetness period, plant age and branch position of cylindrocladium leaf blight and defoliation severity were assessed in greenhouse studies using two Eucalyptus grandis × E. urophylla hybrid clones. Penetration occurred through stomata, and there was no difference in the number of penetrations between young and old leaves. Percentage leaf area with lesions and defoliation increased with the increase in inoculum concentration (1 × 102 to 105 conidia mL−1), duration of leaf wetness period (6 to 48 h) and plant age (60 to 180 days). Branch position in plants also significantly affected the percentage leaf area with lesions and defoliation, the latter variable being significantly higher at the stem base. The highest values of lesion area were also observed on leaves at the stem base in both clones. The Pearson correlation between defoliation and leaf area with lesions was significant in all experiments (r > 0·9) indicating a high association between these two variables.

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Bacterial leaf blight of eucalyptus is initially characterized by water soaked, angular, amphigenous and interveinal lesions, concentrated along the main vein, at the edges or scattered on the leaf blade. As the disease progresses, the lesions become brown to pale, and when young leaves are infected leaf cut areas at the edges or perforations at the center of the lesions may appear due to abortion of the necrotic area. Eventually, necrosis may be found on petiole and twigs. Leaf fall commonly occurs on highly susceptible genotypes due to the early senescence of diseased leaves. Precise diagnosis is accomplished by bacterial exudation from leaf sections placed in a water drop under light microscope (200 x). Twenty-five bacterial isolates from Amapá (2), Bahia (4), Minas Gerais (2), São Paulo (9), Pará (3), Mato Grosso do Sul (1), and Rio Grande do Sul (4) States, which induced hypersensitive reaction (HR) in non-host plants and were pathogenic to eucalyptus, when inoculated by inoculum injection, were identified by biochemical assays, using carbon sources (MicroLog TM BIOLOG) and sequence analysis (16S rDNA). Ten isolates were identified as Xanthomonas axonopodis, four as X. campestris, four as Pseudomonas syringae, two as P. putida, two as P. cichorii, one as Erwinia sp., and two were similar to bacterial genera of Rhizobiaceae. When spray inoculated on intact plants of eucalyptus, only X. axonopodis, P. cichorii and isolates of the Rhizobiaceae family induced typical symptoms of the disease and were considered pathogenic. In Brazil, X. axonopodis seems to be the most widespread species causing the bacterial leaf blight of Eucalyptus spp. Keywords: Eucalyptus, Xanthomonas, Pseudomonas, Erwinia, Rhizobiaceae. RESUMO Etiologia da mancha foliar bacteriana em eucalipto no BrasilA mancha foliar bacteriana do eucalipto caracteriza-se inicialmente por lesões encharcadas do tipo anasarca, internervurais, encharcadas do tipo anasarca, internervurais, angulares e anfígenas, concentradas ao longo da nervura principal, nas margens da folha ou distribuídas aleatoriamente sobre o limbo. Com o progresso da doença, as lesões adquirem aspecto ressecado e coloração marrom a palha, podendo conter orifícios no centro da lesão ou áreas recortadas do limbo em conseqüência do aborto da área necrosada, principalmente em folhas mais jovens. Eventualmente pode haver necrose em pecíolo e ramos. A doença culmina com a desfolha devido à senescência precoce das folhas infectadas. O diagnóstico inequívoco é realizado por meio de exsudação de pus bacteriano a partir de fragmento de folha infectada, sob microscópio óptico de luz (200 x). Vinte e cinco isolados oriundos dos estados do Amapá (2), Bahia (4), Minas Gerais (2), São Paulo (9), Pará (3), Mato Grosso do Sul (1) e Rio Grande do Sul (4) indutores de reação de hipersensibilidade em plantas não-hospedeiras e, patogênicos ao eucalipto em testes de injeção de suspensão bacteriana no mesófilo foliar, foram identificados por meio de testes bioquímicos, utilização de fontes de carbono e...

A total of 107 rhizobacterial isolates, obtained from the rhizosphere of eucalypt clones were tested as rooting inducers of cuttings and mini-cuttings planted in substrate composed of carbonized rice husk and vermiculite (1:1). Cuttings and mini-cuttings were planted in conical plastic tubes containing treated and untreated (control) substrate and kept under intermittent mist irrigation at 26-28ºC. After 35 days, rooting percentage and dry root matter of cuttings were evaluated. Ten isolates capable of providing gains of up to 110% in root formation and up to 250% in root biomass over non-inoculated control cuttings were selected. Gains in rooting varied according to clone and isolate tested. The greatest gains were obtained for the mini-cuttings exhibiting the lowest rooting efficiency. Among the ten isolates tested, only 3918 (code R98) and MF4 (code R87), produced 3-indole-acetic acid in vitro, at concentrations of 0.7 and 0.67 µg ml -1 , respectively. Significant increases in rooting and root dry matter of cuttings grown on rhizobacteria-inoculated substrate were found when compared to untreated or indole-butyric acid (IBA) treated mini-cuttings.

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