Ricardo Mezzomo

Trichoderma spp no biocontrole de cylindrocladium candelabrum em mudas de eucalyptus saligna

This study tested the effects of commercial biocontrol products on in vitro and in vivo trials against the fungal pathogen Cylindrocladium candelabrum Viegas, leaf blight agent on Eucalyptus saligna. The in vitro tests (direct confrontation and inoculation on detached leaves of E. saligna) were composed by the following treatments: T1 - only C. candelabrum, T2 - 06006S isolate x C. candelabrum, T3 - 53RR isolate x C. candelabrum, T4 - 5D isolate x C. candelabrum; T5 -Agrotrich® x C. candelabrum and T6 - Trichodel® x C. candelabrum. All isolates were efficient in controlling the growth of the pathogen during the direct confrontation test; similarly, Trichoderma spp. 53RR and 06006S, as well as the commercial product Trichodel ®, controlled the symptoms on the detached leaves. In order to complement the in vitro tests, the commercial products Agrotrich® and Trichodel® were tested on E. saligna seedlings cultivated in greenhouse. The following treatments were applied: T1 - control - plants without inoculation; T2 - plants inoculated with C. candelabrum; T3 - plants inoculated with C. candelabrum x Agrotrich®; T4 - plants inoculated with C. candelabrum x Trichodel®; T5 - plants inoculated with Agrotrich® and T6 - plants inoculated with Trichodel®. Trichodel® reduced C. candelabrum damage on E. saligna seedlings.

FIRST REPORT OF SPECIES IN THE CLADOSPORIUM CLADOSPORIOIDES COMPLEX CAUSING PECAN LEAF SPOT IN BRAZIL

From January to April 2014, sixteen pecan (Carya illinoinensis) orchards in southern Brazil were surveyed to determine the causal agent of a small black circular leaf spot disease. Forty isolates obtained on potato dextrose agar (PDA) were identified on the basis of morphological features and sequence analysis of the translation elongation factor 1-α gene (Bensch et al., 2012). Morphological features and sequence homology confirmed the isolates to be either Cladosporium cladosporioides, C. pseudocladosporioides or C. subuliforme, all species included in the C. cladosporioides complex. On PDA, C. cladosporioides (2/1PR, GenBank accession No. KT991541) and C. pseudocladosporioides (11RS, KT991560) both produced colonies of greenish-gray pigmentation with velvety and floccose aerial mycelium, whereas C. subuliforme (16/2RS, KT995114) produced colonies with similar pigmentation but more abundant aerial mycelium. Isolates 2/1PR, 11RS and 16/2RS produced on average colonies that were 72.2, 68.1 and 74.6 mm in diameter, respectively; conidia were 5.1 × 2.6 μm, 5.7 × 2.5 μm and 5.3 × 2.9 μm in length; ramoconidia were 23.7 × 4.2 μm, 22.5 × 2.8 μm and 16.0 × 4.3 μm in length. To confirm pathogenicity, young detached leaflets were inoculated with twenty-six isolates. One-tenth ml of conidial suspension (1 × 106 conidia ml-1) divided into six individual drops was applied on each leaflet surface with eight replicates. Leaflets receiving only sterile distilled water served as a non-inoculated control. Black leaf spots were observed after 22 days on all inoculated leaflets. The original Cladosporium species was re-isolated from inoculated leaflets. To our knowledge, this is the first report of C. cladosporioides, C. pseudocladosporioides and C. subuliforme causing pecan leaf spot in Brazil as well as in the world.

CARACTERIZAÇÃO MORFOLÓGICA, MOLECULAR E PATOGENICIDADE DE Fusarium acuminatum E Fusarium verticillioides A Cordia americana

Cordia americana (L.) Gottschling & J. S. Mill. (guajuvira) is a forest species widely distributed in Brazil and represents environmental and economic importance due to the quality of its timber and use in reforestation. In order to evaluate the pathogenicity of Fusarium sp. associated with seeds, characterizing the isolates morphologically and molecularly in order to identify them on the species level, was obtained four fungal isolates that were inoculated in seeds to demonstrate their pathogenicity. The morphological characterization was performed using an identification key for the genus Fusarium and, for the molecular identification, genomic regions Internal Transcribed Spacer (ITS) were sequenced with its elongation factor 1 alpha (TEF1-α). The results of the molecular identification agreed with the morphological characterization and allowed to identify the species Fusarium acuminatum and Fusarium verticillioides , both being pathogenic to Cordia americana , causing damping-off in pre and post emergence, and rotting of roots and necrosis of hypocotyl.

INFLUÊNCIA DA INOCULAÇÃO DE Fusarium spp. E NÍVEIS DE SOMBREAMENTO NO CRESCIMENTO E DESENVOLVIMENTO DA ERVA-MATE

The “erva-mate” ( Ilex paraguariensis A. St.-Hill) is a species broadly cultivated in southern Brazil and neighboring countries, whose leaves and fine branches, prepared according to the appropriate method, make the “mate” or “chimarrao”, the most popular tea consumed in Brazil and exported around the world. With an increasing planted area, mainly in the last decade, phytosanitary problems caused by pests and disease have increased in this crop and root-rot is becoming one of the main problems. The disease is caused by Fusarium spp. and it causes serious damage to the roots, in the most serious cases, leading to the death of the plant. The “erva-mate” is a species that inhabits the forest underwood, and cultivation in a homogeneous way to full sun can be a stressful factor for the species causing less growth and development and, also, more susceptibility to root-rot. Therefore, experiments were conducted in the Forest Nursery area belonging to Forest Sciences Department of the Federal University Santa Maria with the objective of confirming these assumptions. The experiment was conducted in a factorial design (2 x 5), composed by Fusarium spp. inoculation and by shading levels. It was verified that plants submitted to lower shading levels or full sun had less development and were more susceptible to the disease. The plants inoculated with Fusarium spp. had less development in comparison with non-inoculated plants, mainly at the lower shading levels.

Trichoderma spp. na Produção de Mudas de Espécies Florestais

Seeds healthy and rapid development of seedlings of native species may be critical to the success of your establishment. This study evaluated the effect of Trichoderma spp. on seed and seedling development of Parapiptadenia rigida (angico), Cedrela fissilis (cedro) and Pelthophorum dubium (canafistula). The fungi was applied at different times of the production of seedlings. The fungi action was different between species and between the variables. Cedro was less responsive to application of Trichoderma spp. at any time of the seedlings production and the association of Trichoderma spp. With angico as the seed treatment favored the incidence of some pathogens, however the application later favored only the leaves development. In canafistula, the seed treatment provided control of pathogens associated and stimulated the emergence and production of leaves in seedlings, have potential to be used for seed treatment of this species.

Qualidade fisiológica e tratamentos de sementes de cedrela fissilis procedentes do sul do Brasil

Os objetivos deste trabalho foram: avaliar a qualidade fisiologica de sementes de cedro (Cedrela fissilis), procedentes de localidades do sul do Brasil, atraves de testes de vigor e avaliar diferentes tratamentos nas sementes para controle de patogenos e para promocao da germinacao da especie. Para tanto, foram utilizadas seis amostras com procedencias dos Estados do Rio Grande do Sul, Santa Catarina e Parana, as quais foram submetidas a determinacao de teor de agua, teste de germinacao e primeira contagem, envelhecimento acelerado (testando periodos de exposicao as condicoes de envelhecimento), emergencia em viveiro e tratamento de sementes. Os tratamentos utilizados para controle de patogenos foram: testemunha (T0); fisico com calor seco a 70°C±3°C por 48 horas (T1); extrato aquoso de alho (Allium sativum) (T2); biologico a base de Trichoderma spp. - Agrotich Plus® (T3); e quimico com fungicida protetor Captan (T4). A germinacao variou de 56 a 87%; o periodo de 48 h sob temperatura de 41 °C foi o mais eficiente para estratificar as amostras em niveis de vigor; a emergencia variou de 51 a 88% e as variaveis de desempenho de plântulas analisadas conseguiram estratificar as amostras em niveis de vigor. Quanto ao tratamento de sementes, o calor seco e o tratamento a base de extrato de alho se mostram eficientes no controle de microrganismos em semente de cedro, sem prejuizos ao vigor destas.

Inoculação de Fusarium oxysporum e Fusarium solani e níveis de sombreamento na erva-mate: influência na severidade da podridão-de-raízes

Ilex paraguariensis A. St.-Hill is a broadly cultivated species in the South of Brazil. With the increasing planted area, mainly in the last decade, fitosanitary problems caused by pest and diseases have increased in this crop, and the root-rot is becomin g one of the main problems. Among the pathogens, Fusarium oxysporum Schlecht. and Fusarium solani (Mart.) Sacc are the main ones. These fungi provoke severe damages resulting in the destruction of the root system and, in the most serious cases, they ca use the death of the plant. It is suspected that the incide nce and severity of disease are influenced by culti vation of Ilex paraguariensis in different levels of shading or full sun. Theref ore, experiments were conducted in the Forest Nursery area belonging to Forest Sciences De partment/CCR/UFSM with the objective of confirming this assumption. The experiment was conducted in a factorial design (2 x 5), composed by Fusarium oxysporum and Fusarium solani inoculation and by shading levels. It was verified that the plants submitted to lower shading levels or full sun had their predi sposed to the disease.