Micobiota fitopatogência das plantas daninhas Bidens pilosa e Bidens subalternans no Brasil
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2011-02-21
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Universidade Federal de Viçosa
Resumo
O chamado “complexo Bidens” é um conjunto de espécies de plantas da família Asteraceae que inclui Bidens pilosa (picão preto) e Bidens subalternans (picão amarelo). Estas espécies de plantas daninhas são de grande importância devido aos problemas que causam para a agricultura brasileira e mundial. O manejo destas duas espécies tem sido dificultado com o surgimento e disseminação de biótipos resistentes a herbicidas. O controle biológico, já explorado no manejo de outras espécies de plantas daninhas, nunca foi estudado para plantas do “complexo Bidens”. Neste trabalho, investigaram-se os fungos associados a estas duas espécies de plantas no Brasil, com vistas a explorar seu potencial de utilização como agentes de controle biológico. Levantamentos foram efetuados num período de vinte e dois meses, incluindo localidades em oito estados brasileiros e resultando na coleta de noventa e sete amostras. Dez espécies fúngicas foram encontradas associadas à B. pilosa (Bp) e doze associadas a B. subalternans (Bs): Colletotrichum sp. (Bs) (antracnose), Cercospora bidentis (Bp e Bs), Cercospora maculicola (Bp e Bs) (manchas foliares); Entyloma bidentis (Bp e Bs), Entyloma compositarum (Bp) e Entyloma guaraniticum (Bp e Bs) (carvão branco); Golovinomyces cichoracearum var. cichoracearum (Bp e Bs) (míldio pulvurulento); Plasmopara halstedii (Bp e Bs) (míldio verdadeiro); Pseudocercosporella sp. nov. (Bs) (mancha foliar); Podosphaera fusca (Bp e Bs) (míldio pulvurulento); Sphaceloma bidentis (Bs) (verrugose); Uredo bidentis (Bp e Bs) e Uromyces bidentis (Bp e Bs) (ferrugens). O estudo demonstrou o grande desconhecimento sobre a micobiota destas importantes espécies de plantas invasoras. Todas as associações fungo-hospedeiro, com a exceção de C. bidentis, E. bidentis, Uredo bidentis, e Uromyces bidentis, sobre B. pilosa e G. cichoracearum var. cichoracearum e Uredo bidentis sobre B. subalternans representam relatos novos para o Brasil. Além disto, uma nova espécie (Pseudocercosporella sp. nov.) foi encontrada e será proposta. Uma discussão sobre a taxonomia dos fungos coletados é apresentada. Foi comprovada a patogenicidade de Colletotrichum sp., C. bidentis, C. maculicola e S. bidentis tanto a B. pilosa, quanto a B. sublaternans, sendo que apenas Colletotrichum sp. e S. bidentis, demonstraram potencial aparente como agentes de biocontrole.
The Bidens complex is a set of plant species of the Asteraceae family which includes Bidens pilosa and Bidens subalternans (Hairy’s beggarticks or Spanish needles) two species of weeds with great importance which cause many problems for Brazilian’s agriculture and in the world. The management of these species has been difficult with the emergence and spread of herbicide resistant biotypes. Biological control, as explored in the management of other weed species, has never been studied for plants of the Bidens complex. In this study, we investigated the fungi associated with these two species in Brazil, with a view to exploring their potential use as biological control agents. Surveys were conducted over a period of twenty-two months, including locations in eight states and resulting in the collection of ninety-seven samples. Ten fungal species were found on B. pilosa (Bp) and twelve associated with B. subalternans (Bs): Colletotrichum sp (Bs) (anthracnose), Cercospora bidentis (Bp and Bs), Cercospora maculicola (Bp and Bs) (leaf spots); Entyloma bidentis (Bp and Bs), Entyloma compositarum (Bp) and Entyloma guaraniticum (Bp and Bs) (white smuts); Golovinomyces cichoracearum var. cichoracearum (Bp and Bs) (powdery mildew); Plasmopara halstedii (Bp and Bs) (downy mildew); Pseudocercosporella sp. nov. (Bs) (leaf spot); Podosphaera fusca (Bp and Bs) (powdery mildew); Sphaceloma bidentis (Bs) (scab); Uredo bidentis (Bp and Bs) and Uromyces bidentis (Bp and Bs) (rusts). The study demonstrated the widespread ignorance on the mycobiota of these two important species of invasive plants. All fungus-host associations, with the exception of C. bidentis, E. bidentis, Uredo bidentis, and Uromyces bidentis, on B. pilosa and G. cichoracearum var. cichorarearum and Uredo bidentis on B. subalternans, represent new reports for Brazil. Moreover, a new species (Pseudocercosporella sp. nov.) was found and will be proposed. A discussion on the taxonomy of fungi collected is presented. The pathogenicity of Colletotrichum sp., C. bidentis, C. maculicola, and S. bidentis either to B. pilosa or to B. sublaternans, was demonstrated. Only Colletotrichum sp. and S. bidentis showed potential as biocontrol agents.
The Bidens complex is a set of plant species of the Asteraceae family which includes Bidens pilosa and Bidens subalternans (Hairy’s beggarticks or Spanish needles) two species of weeds with great importance which cause many problems for Brazilian’s agriculture and in the world. The management of these species has been difficult with the emergence and spread of herbicide resistant biotypes. Biological control, as explored in the management of other weed species, has never been studied for plants of the Bidens complex. In this study, we investigated the fungi associated with these two species in Brazil, with a view to exploring their potential use as biological control agents. Surveys were conducted over a period of twenty-two months, including locations in eight states and resulting in the collection of ninety-seven samples. Ten fungal species were found on B. pilosa (Bp) and twelve associated with B. subalternans (Bs): Colletotrichum sp (Bs) (anthracnose), Cercospora bidentis (Bp and Bs), Cercospora maculicola (Bp and Bs) (leaf spots); Entyloma bidentis (Bp and Bs), Entyloma compositarum (Bp) and Entyloma guaraniticum (Bp and Bs) (white smuts); Golovinomyces cichoracearum var. cichoracearum (Bp and Bs) (powdery mildew); Plasmopara halstedii (Bp and Bs) (downy mildew); Pseudocercosporella sp. nov. (Bs) (leaf spot); Podosphaera fusca (Bp and Bs) (powdery mildew); Sphaceloma bidentis (Bs) (scab); Uredo bidentis (Bp and Bs) and Uromyces bidentis (Bp and Bs) (rusts). The study demonstrated the widespread ignorance on the mycobiota of these two important species of invasive plants. All fungus-host associations, with the exception of C. bidentis, E. bidentis, Uredo bidentis, and Uromyces bidentis, on B. pilosa and G. cichoracearum var. cichorarearum and Uredo bidentis on B. subalternans, represent new reports for Brazil. Moreover, a new species (Pseudocercosporella sp. nov.) was found and will be proposed. A discussion on the taxonomy of fungi collected is presented. The pathogenicity of Colletotrichum sp., C. bidentis, C. maculicola, and S. bidentis either to B. pilosa or to B. sublaternans, was demonstrated. Only Colletotrichum sp. and S. bidentis showed potential as biocontrol agents.
Descrição
Palavras-chave
Bidens pilosa, Bidens subalternans, Fungos fitopatogênicos - Controle biológico, Asteraceae
Citação
GUATIMOSIM, Eduardo. Micobiota fitopatogência das plantas daninhas Bidens pilosa e Bidens subalternans no Brasil. 2011. 83 f. Dissertação (Mestrado em Fitopatologia) - Universidade Federal de Viçosa, Viçosa. 2011.