Arailde Fontes Urben

Cylindrocarpon destructans causador do "pé-preto" da videira no Rio Grande do Sul

Since 1999, a death of the American grapevine (Vitis labrusca) has been noted in the state of Rio G rande do Sul, Brazil. The disease is characterized by stem and root rotting followed by wilt and plant death. Based on isolation, pathogenicity confirmation and morphological characteristics, Cylindrocarpon destructans was identified as the causal agent of the disease. This is the first report of black foot on grapevine in Brazil.

Application of Chinese Jun-Cao technique for the production of Brazilian Ganoderma lucidum strains

Ganoderma lucidum is a medicinal mushroom traditionally used in China against a wide range of diseases such as cancer and also for its prevention. In this work, commercial Chinese strains G. lucidum were compared to wild Brazilian strains aiming to determine the cultivation potential through the use of Jun-Cao. Six formulations were tested and the strains presented good response to the applied method. In general, the mixture between the grass and wood was well suited for the basidiomycetes, contributing to the preparation of substrates that generated better results in Jun Cao.

Heliconia psittacorum: hospedeira de Mycosphaerella fijiensis, agente causal da sigatoka-negra da bananeira

In Manaus Amazon, Brazil, in September 2003, spots on leaves of Heliconia psittacorum were observed that were very similar to those of black sigatoka caused by Mycosphaerella fijiensis on Musa spp. The pathogen was isolated and a pathogenicity test was done. An isolate from H. psittacorum and other from banana (Musa spp.) cv. Prata Ana were inoculated on H. psittacorum as well as on banana cv. Prata Ana. In both species the tests were positive. Microscopic observations and the results of pathogenicity tests showed that H. psittacorum is another host of M. fijiensis. This is the first report of M. fijiensis on H. psittacorum.

Use of RAPD molecular markers on differentiation of brazilian and chinese Ganoderma lucidum strains

The aim of this work was to analyze the Brazilian and Chinese strains of Ganoderma lucidum with molecular RAPD markers. A similarity matrix was elaborated and the RAPD profiles of G. lucidum strains were also compared to two other Ganoderma spp: G. applanatum and G. lipsiense in order to produce genetic similarity among the species. Based on the primers used, it was possible to determine that the Brazilian strains and Chinese strain CC-22 are alike. The method and the primers selection showed to be appropriate for the genetic identification of G. lucidum strains, enabling them to be improved and used in research, as well as in the world market.

Interceptação de Phoma exigua var. foveata, praga exótica e quarentenária para o Brasil, em germoplasma de batata procedente da França

Potato tubers from France and introduced to Brazil for research purposes were subjected to phytosanitary analysis at the Quarantine Laboratory of Embrapa Genetic Resources and Biotechnology (Cenargen). Some of the tubers showed sunken, water-soaked, brownish-purple lesions, with soft skin, and black pycnidia were visible in the lesions using a stereomicroscope. Examination of the fungal structures on microscope slides using light microscopy demonstrated that the fungus had the morphology of Phoma exigua var. foveata, an A1 quarantine pest for Brazil. Pathogenicity tests were carried out inoculating healthy potato tubers with a pure culture of the fungus. Rot symptoms were observed 3 days after inoculation and progressed until 8 days. The fungus was re-isolated from the lesions on potato dextrose agar, confirming that the fungus was the etiological agent of the disease. The tubers that were symptomatic were incinerated, and the other healthy-looking tubers were treated with a systemic fungicide, cultivated under quarantine for two generations, and then reanalyzed. After confirming that they were free of the pathogen, the tubers were sent to their destination solicitor.