Substrates and cover crop residues on the suppression of sclerotia and carpogenic germination of Sclerotinia sclerotiorum/Substratos e resíduos de plantas de cobertura na supressão dos escleródios e germinação carpogênica de Sclerotinia sclerotiorum

Cover crops influence populations of microorganisms, such as a pathogen. In this work the objective was to evaluate the influence of different cover crops on the sclerotia of Sclerotinia sclerotiorum recovering rate in soil as well as the mycelial growth rate for recovered sclerotia. The influence of different substrates for carpogenic germination was also evaluated. The cover crops used in the experiment were Crotalaria juncea L., Urochloa ruziziensis R. Germ. & Evrard, Panicum maximum cv. Mombaca Jacq., Pennisetum glaucum (L.) R. Brown, Cajanus cajan (L.) Millsp.) and Stylosantes capitata Vog.; Stylosanthes macrocephala Ferr. Et Costa). The substrates used for carpogenic germination were agar-water, agar- water + filter paper, sand and mixed sand and soil. The cover crops showed efficiency in the suppression of S. sclerotiorum, especially for Stylosanthes spp. and Panicum maximum cv. Mombaca in the rate recovering of sclerotia and for Stylosanthes spp. in the rate of mycelial growth by providing a suitable environment for growth of antagonistic microorganisms. As for the number of carpogenic germinated sclerotia and for the number of apothecia formed on different substrates, the sand; agar-water and soil + sand mixture stood out, respectively. Key-Words: white mold, cultural management, biological control; apothecia; biomass Substratos e residuos de plantas de cobertura na supressao dos esclerodios e germinacao carpogenica de Sclerotinia sclerotiorum Resumo As plantas de cobertura influenciam as populacoes de microrganismos, tal como o fitopatogeno. Neste trabalho o objetivo foi avaliar a influencia de diferentes plantas de cobertura sobre a taxa de recuperacao dos esclerodios de Sclerotinia sclerotiorum no solo, bem como o indice da velocidade de crescimento micelial para os esclerodios recuperados. Avaliou-se tambem a influencia de diferentes substratos para germinacao carpogenica. As plantas de cobertura utilizadas no experimento foram Crotalaria juncea L., Urochloa ruziziensis R. Germ. & Evrard, Panicum maximum cv. Mombaca Jacq., Pennisetum glaucum (L.) R. Brown, Cajanus cajan (L.) Millsp.) e Stylosantes capitata Vog.; Stylosanthes macrocephala Ferr. Et Costa). Os substratos utilizados para a germinacao carpogenica foram agar-agua, agar-agua+papel filtro, areia e mistura areia e solo. As plantas de cobertura apresentaram eficiencia na supressao de S. sclerotiorum, com destaque, para Stylosantes spp. e Panicum maximum cv. Mombaca quanto a taxa de recu