Edival A. V. Zauza

Myrtaceae species resistance to rust caused by Puccinia psidii

Seeds from different species and provenances of Myrtaceae, collected from wild populations in Australia, were screened for resistance to rust caused by Puccini psidii. Seedlings were inoculated with a suspension of rust inoculum and incubated in a mist chamber in the dark for 24 h. Subsequently, the plants were transferred to a growth chamber and rust reaction was evaluated 12 days later. Inter- and intra-specific variability was observed among and within the myrtaceae species. Independent of the provenance, the most resistant species were: Corymbia calophylla ‘rosea’, C. tesselaris, Melaleuca ericifolia, Eucalyptus tereticornis, E. resinifera, E. scias subsp. scias, E. paniculata, E. pellita and C. intermediata. In contrast, M. nesophila, M. alternifolia, M. cajuputi subsp. cajuputi, M. leucadendra, M. quinquenervia, E. cloeziana, E. diversicolor, E. regnans and E. grandis displayed the highest number of susceptible plants. Among those additional myrtaceaceous genera which were tested for their reaction to rust the most resistant were Asteromyrtus dulcia, A. tenuifolia, Gossia fragrantissima, Lophostemon confertus, Syzygium australe, S. wilsonii subsp. cryptophlebium, Archirhodomytus beckleri, Acmena smithii and Syzygium alatoramulum. Pericalymma ellipticum, Kunzea baxteri, Astartea heteranthera, Regelia ciliata, Rhodomyrtus psidioides and Syncarpia glomulifera were the most susceptible species.

First record of Puccinia psidii on Eucalyptus globulus and E. viminalis in Brazil

Asevere attack of Puccinia psidii was observed in commercial plantations of Eucalyptus globulus and E. viminalis in the Guaiba-RS, Brazil on July 2000. The disease severity was highly variable among plants of both species. Hybrids of E. viminalis were apparently more susceptible than the pure species.

Sporothrix eucalypti a new pathogen of eucalyptus in Brazil

Sporothrix eucalypti a new pathogen of eucalyptus in Brazil Sporothrix eucalyp t i i s reported for t h e f i r st t ime in Brazil causing stem girdling on seedlings of Eucalyp tus g lobulus , l ea f and shoot b l igh t o n ministumps of a hybrid of Eucalyptus sa l igna x E . m a i d e n i i , u s e d a s s o u r c e o f s p r o u t s f o r mininicuttings. Registrou-se, em marco de 2000, a ocorrencia de uma nova doenca de Eucalyptus sp., em minijardim clonal, na regiao de Barra do Ribeiro – RS. A epoca da inspecao, a doenca encontrava-se restrita a um clone hibrido de Eucalyptus saligna Smith x E. maedenii Fmuell e, subsequentemente, em mudas seminais de E. globulus Labill. A enfermidade, aqui designada de esporotricose do eucalipto, caracteriza-se pela infeccao da haste principal de mudas (Figura 1A) e de porcoes apicais de brotacoes de minicepas produtoras de brotos para enraizamento (Figura 1B) e folhas (Figura 1C). Nas folhas, as lesoes sao inicialmente arroxeadas, ligeiramente arredondadas, ou de formato e dimensoes variaveis. No caule e peciolo, o patogeno induz anelamento e morte dos mesmos. Os orgaos afetados, nao raro, tornam-se retorcidos e as areas necroticas escuras recobertas com pustulas esbranquicadas (massa de micelio, conidioforos e conidios) de um fungo, com caracteristicas morfologicas tipicas de Sporothrix eucalypti Wingfield, Crous & Swart, relatado em Eucalyptus sp., na Africa do Sul (Wingfield et al., 1993, Mycopathologia 123:159-164). Suas colonias, em BDA, possuem odor peculiar, sao brancas e esporulantes (Figura 1D); seus conidios primarios (5-10 x 2,55 μm) e secundarios (2,5-5 x 1,0-2,5 μm) sao hialinos, unicelulares, produzidos em celulas conidiogenicas denticuladas, hialinas e diferenciadas da hifa vegetativa (Figuras 1 E, F e G). A temperatura otima de crescimento e 25 oC, onde apos 10 dias de incubacao, no escuro, atinge uma media de 512 mm. Para os testes de patogenicidade do fungo, 15 mudas sadias de E. globulus foram atomizadas com uma suspensao de inoculo a 2,5 x 10 conidios/ml. Apos a inoculacao, as mudas foram mantidas em câmara umida no escuro por tres dias a 25 oC. Os primeiros sintomas e sinais da doenca surgiram aos 14 dias da inoculacao e caracterizaram-se pelo surgimento de lesoes escuras, contendo esporulacoes branca do patogeno. A reproducao dos sintomas da doenca por inoculacao artificial em todas as mudas inoculadas e o reisolamento do fungo para BDA, a partir de tecidos infetados, confirmaram a etiologia da doenca. A B

Vertical spread of Puccinia psidii urediniospores and development of eucalyptus rust at different heights

Rust, caused by Puccinia psidii, is an important disease in eucalyptus nurseries and plantations in Brazil. In the field, eucalyptus plants taller than 3–4 m are not infected by the pathogen. We hypothesised that microclimatic conditions above 3 m do not favour either pathogen establishment or disease development. Therefore, we evaluated the effect of the height gradient on rust incidence, related to leaf wetness duration and the number of airborne urediniospores. Young eucalyptus plants were maintained at heights from 0.5 to 4.0 m, and disease was assessed weekly at all heights in five plant sets. Rust incidence reduced as height increased. The values of area under rust progress and rust incidence were negatively correlated (P ≤ 0.05) with height and positively correlated (P ≤ 0.05) with the number of both hours with leaf wetness and airborne urediniospores. Thus establishment and progress of eucalyptus rust were affected by leaf wetness duration and concentration of airborne urediniospores, which decreased as the height increased.

Etiologia do oídio do eucalipto

Isolates of Oidium spp. from Eucalyptus pellita were compared to Erysiphe cichoracearum, obtained from Dahlia sp. and Sphaerotheca pannosa, from Rosa sp. Based on the morphological characteristics of the anamorph, it was concluded that the Oidium isolate from eucalypt was similar to the isolate from rose identified as S. pannosa. Inoculations of Oidium isolates from all studied host species showed that S. pannosa obtained from eucalypt and rose, and E. cichoracearum from Dahlia sp. were pathogenic to seedlings of Eucalyptus pellita, one of the most susceptible species to the pathogen, under greenhouse conditions.Compararam-se isolados de Oidium sp. obtidos de mudas de eucalipto (Eucalyptus spp.) com isolados de Erysiphe cichoracearum, originario de dalia, e Sphaerotheca pannosa de roseira (Rosa sp.), por meio de caracteristicas morfologicas. Com base nas caracteristicas morfologicas (fase anamorfica) do tubo germinativo, do micelio, do apressorio, de conidioforos e conidios e na presenca de corpos de fibrosina, concluiu-se que o isolado de Oidium, obtido de eucalipto e similar ao de roseira, descrito como S. pannosa. Inoculacoes dos isolados do fungo originarios de todos os hospedeiros estudados, indicaram que S. pannosa, obtido de roseira, e E. cichoracearum, de dalia (Dahlia sp.), foram patogenicos a mudas de Eucalyptus pellita, uma das especies mais suscetiveis a esta doenca, em condicoes de casa de vegetacao.

Germinação de Conídios de Sphaerotheca pannosa Obtidos de Eucalipto

Estudou-se a germinacao de conidios de Sphaerotheca pannosa em diferentes meios-suporte sob diferentes regimes de umidade relativa, fotoperiodo e temperatura. As 24 h da incubacao, avaliou-se a germinacao em agar-agua, lâmina de vidro e folha destacada, sob condicoes de câmara umida. Nao se constatou germinacao de conidios em lâmina de vidro escavada, ou placas de Petri, na presenca de agua livre. A germinacao do patogeno foi favorecida por umidade relativa proxima a 100%, fotoperiodo de 12 h, com exposicao inicial a luz e temperaturas de 20 a 25 oC.

First report of phytoplasma associated with Eucalyptus urophylla showing witches’ broom in Brazil

Eucalyptus production is of great importance to Brazils economy. Diseases affecting the growth and the architecture of these trees lead to large losses in yield and quality of the wood. The occurrence of eucalyptus trees showing witches’ broom and little leaf symptoms in different areas of Brazil is affecting seedling production. In this work, a phytoplasma was found associated with these symptomatic plants and was identified as belonging to the 16SrII group. This is the first report of a phytoplasma associated with eucalyptus in Brazil.

Eugenia brachypoda, new host of Cylindrocladium pteridis in the State of Pará, Brazil.

The socoro (Eugenia brachypoda DC) belongs to the Myrtaceae family and voluntarily grows on the margins of rivers and lakes in the micro-region of mid-Amazon. The mature fruits are round and orange to purple in color; the sweet and sour pulp is highly appreciated by the local population, especially of Monte Alegre and Alenquer in the State of Para. In June 1996, seedlings were raised from seeds obtained from the fruits collected from the margin of the LakeArariquara in Alenquer-PA, and planted on uplands in the experimental fields of Embrapa in the eastern Amazon, in Belem, Para. Leaf spots of irregular size and shape (Figure 1), resulting in leaf desiccation and defoliation were observed in May 2002. The fragments from diseased leaf tissues were cut from the margins of the leaf spots, surface disinfected in 1% sodium hypochlorite for 1 min, rinsed in sterile water and plated on 2% water agar. The colonies that developed after three days of incubation at room condition were transferred to PDA, where the fungus showed morphological characteristics typical of Cylindrocladium pteridis Wolf (Figure 1B), teliomorph Calonectria pteridis Crous, Wingfield & Alfenas. The cylindrical, hyaline, uniseptate conidia measuring 65 76 μm x 4.6 5.4 μm (av. 70 x 4.9 μm) were characterized by a clavate vesicle. The fungus has been reported from Brazil as causing lesions on Pinus caribaea Morolet var. hondurensis Barr. & Golfari (Hodges et al. Brasil florestal 6:8-11. 1975), coconut (Cocus nucifera L.) (Silva & Souza, Fitopatol. bras. 6:515-517. 1981; Ponte & Silveira Filho. Fitopatol. bras. 22:567. 1997; Trindade et al. Fitopatol. bras. 23:412. 1998), in buritizeiro (Mauritia flexuosa L.) (Silva Fitopatol. bras. 21:523. 1996) and in Eucalyptus spp. (Ferreira et al., 1992. Fitopatol. bras. 17:226.1992). The pathogenicity test was done by inoculating the host leaves with a PDA culture disc of C. pteridis, and incubating in a

Cylindrocladium pteridis em Palmeiras Ornamentais

Cylindrocladium pteridis on Ornamental Palms Cylindrocladim pteridis is first described as causal agent of leaf blight on Washingtonia filifera and Veitchia merrilli in the State of Maranhão, Brazil. The fungus was isolated in vitro and identified based on its morphological characteristics. As palmeiras ornamentais são amplamente utilizadas em projetos paisagísticos, tanto urbano quanto em jardins particulares, alcançando, algumas delas, elevados preços no mercado. Durante o ano de 2003, diversas amostras da palmeira da Califórnia [Washingtonia filifera (L.) Wendl.] foram recebidas para análise no Laboratório de Fitopatologia da Universidade Estadual do Maranhão. Plantas jovens apresentavam folhas com manchas encharcadas (anasarca), medindo até 1 cm de diâmetro (Figura 1A) que, quando coalesciam atingiam grandes porções do limbo. Na face abaxial das folhas, sobre as lesões, era possível observar abundante esporulação do patógeno. Lâminas preparadas a partir de raspagem direta das lesões revelaram a presença de um fungo do gênero Cylindrocladium o qual foi facilmente cultivado em meio de BDA. O patógeno foi identificado como C. pteridis Wolf, com base nas características morfológicas de conídios, dos conidióforos e vesículas (Figura 1C), de acordo com Crous & Wingfield (A monography of Cylindrocladium, including anamorphs of Calonectria, Mycotaxon 51:341-435. 1994). Embora a fase teliomórfica do fungo tenha sido descrita como Calonectria pteridis Crous, Wingfield & Alfenas (Mycotaxon 46:228. 1993), no presente estudo, estruturas sexuais do fungo não foram encontradas. Em inspeções realizadas em floriculturas e viveiros de plantas ornamentais, verificou-se que a mesma doença ocorria em Palmeira de Manilla [Veitchia merrilli (Becc) H.E. Moose] causando manchas necróticas de coloração marronavermelhadas, afetando grandes áreas do tecido foliar (Figura 1B). Testes de patogenicidade em mudas de palmeira da Califórnia e palmeira de Manilla comprovaram a etiologia da doença. Cylindrocladium pteridis tem sido ralatado em representantes da família Palmae no Brasil, tais como coqueiro (Cocos nucifera L.) (Silva & Sousa, Fitopatologia Brasileira 6:515-517.1981), Mauritia flexuosa L. (Silva, Fitopatologia Brasileira 21:523.1996), Cariota mitis Loureiro (Coelho Netto et al., Fitopatologia Brasileira 28:569. 2003). Este é o primeiro FIG. 1 – Sintomas de Cylindrocladium pteridis em palmeiras ornamentais. Amanchas em folhas de Washingtonia filifera; B – manchas em folhas de Veitchia merrilli; C – Estruturas típicas de C. pteridis. relato de C. pteridis causando doença em W. filifera e Veitchia merrilli no Brasil.

Cylindrocladium pteridis leaf spot of apricot tree in the State of Para, Brazil.

The apricot (Mammea americana L.) is a fruit-bearing tree growm throughtout the entire Amazon region, especially in the state of Para, hence the name abrico-of-Para (Cavalcante. Frutas Comestiveis da Amazonia, 1996). The fruits are used in salads, and in the forms of liquor, jelly and compote, all which keep the taste and flavor for long periods of time. The bark latex and the seed powder of apricot are reported to have an insecticidal effect that efficiently control of ticks, other insects, and animal parasites. Its wood tannins are used in the leather industry (Coral. O Abricoteiro, uma opcao de investimento para o Estado do Para. Boletim Tecnico, SAGRI, 1998). In April 2002, during a routine plant pathological inspection of orchards in Marituba, PA, a generalized attack of a leaf spot disease was observed. Small light brown leaf spots, surrounded by a dark brown halo eventually resulted in the blight of the entire leaf (Figure1 A) and defoliation of the trees. Isolations were made from the lesions by cutting tissues fragments from the lesion margins, which after disinfections in 2% sodium hypochlorite for 1 min and washing in sterile water, were placed on 2% water agar. After a seven-day incubation at 26 + 2 C, the fungal growth showed morphometric characteristics of Cylindrocladium pteridis Wolf (telemorph Calonectrica pteridis Crous et al.). The conidiophores are penicillate, with clavate vesicle and the conidia are cylindrical, hyaline, uniseptate, 65-76 x 4.6-5.5 μm (mean 70 x 4.9 μm) (Figure 1B). For the pathogenicity tests, a 5 mm mycelial disc was placed on healthy apricot seedling leaves, while the PDA discs without the fungus served as control. All seedlings were placed in a moist chamber for 72 h. Symptoms similar to the natural infection appeared on the leaves five days after inoculation while the control seedlings remained healthy. The fungus was reisolated from the lesions. Cylindrocladium pteridis has been reported from Brazil causing lesions on aciculae of Pinus caribea Morelet var. hondurensis ( Senecl.) W.H.G. Barret & Golfari (Hodges et al. Brasil Florestal 6:8. 1975), in Cocus nucifera L. (Silva & Souza. Fitopatologia bras. 6:515. 1981; Ponte & Silveira Filho. Fitopatologia bras. 22:67. 1997; Trindade et al. Fitopatologia bras. 23:412. 1998), in Mauritia flexuosa L. (Silva. Fitopatologia bras. 21:523. 1996) and in Eucaliptus spp. (Ferreira et al. Fitopatologia bras. 17:226.1992). No previous report was found in the literature regarding the occurrence of C. pteridis and symptoms of the foliar lesions on apricot; thus this is the first record of the pathogen on apricot in Brazil.