965 resultados para fungus garden
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Pós-graduação em Agronomia (Proteção de Plantas) - FCA
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Currently, the major method for controlling leaf-cutting ants uses toxic baits containing the insecticide sulfluramide. Such compound presents harmful effects to the environment and to human health, which drive the community’s concerns towards new strategies for controlling these insects. Previous studies showed the occurrence of Syncephalastrum racemosum in nests of the leaf-cutting ants submitted to treatments using insecticides. In order to understand the role of S. racemosum in nests of leaf-cutting ants, the present work investigated the antagonism of S. racemosum towards the leaf-cutting ant-cultivar (Leucoagaricus gongylophorus). Using in vitro essays, we co-cultivated L. gongylophorus and S. racemosum (n= 6 lineages). For comparison, we also used the same setup to test one strain of Escovopsis weberi, since this fungus is considered a specialized parasite of the leaf-cutting ant cultivar. All S. racemosum strains inhibited the growth of L. gongylophorus (ANOVA 2 way, F= 23,61, P< 0,01). The same was observed for E. weberi. There were no significant difference between S. racemosum and E. weberi inhibition (Bonferroni test, P> 0,05). In addition, we verified that all S. racemosum strains colonized and sporulated over the fungus garden up to 96 h after garden fragments without workers were inoculated with spores suspensions. Similar results were observed on gardens that were inoculated with spores of E. weberi. The results indicate that S. racemosum act as antagonist of the leaf-cutting ant cultivar. The putative possibility for using S. racemosum as biological control agent of leaf-cutting ants is discussed in the present work
Escovopsis trichodermoides sp nov., isolated from a nest of the lower attine ant Mycocepurus goeldii
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Annually, mature colonies of Atta ants produce winged males and females, where leave the colony in which they were produced to form new colonies and thus continue the species perpetuation. The foundation of Atta spp. colonies always involves high queen effort, solely responsible for growing the fungus and the care with itself and its offspring. During the foundation there is consumption of body reserves. This study investigated how the environment influences the development of newly founded colonies of leaf cutting ant, Atta sexdens rubropilosa. Therefore, it was compared field colonies collected five months after the nuptial flight and colonies maintained in the laboratory since the nuptial flight. It was analyzed the weight and size of the population (number of workers, larvae, pupae and eggs), the workers size, the volume and weight of the fungus garden and queen effort for the nest foundation (lipid content and weight of queens). In comparison to the field colonies, the laboratory colonies showed higher values in the weight and size of population, the volume and weight of the fungus garden. Measures of workers by class size did not vary between colonies from field and laboratory. The queen effort for nest foundation was higher in field colonies, which showed a lower percentage of fat and lower weight compared to laboratory colonies. These results show that the environment has a strong influence on the colonies development during the foundation, as well as on the physiological status of the queens, and therefore the survival, development and success of the colony, it is a reflection of the queen efforts and of the environment conditions.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)National Science Foundation (NSF)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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That the symbiotic fungus of leaf-cutting ants only occasionally produces the sexual phase makes their identification confusing. This has occurred so rarely, either in laboratory nests, or in unbalanced field nests. that the possibility of contamination of the fungal garden by other fungi cannot be disregarded. In this paper we describe the formation of several basidiomata in a healthy and free-living nest of the leaf-cutting ant Acromyrmex hispidus fallax. The cultivation in vitro of the sterile mycelia (isolated from the fungal garden) with their typical inflated tips, and the similarity of both forms confirmed by RAPD analysis of their genomic DNA. The fungus was identified as Leucoagaricus gongylophorus.
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This paper discusses change and chance in order to develop a language that can then be used to discuss change in the garden. In the process, it puts forward the idea that to garden is to meddle with the teleonomy of the plants, their “will” to grow as they should. Different design conceptions of change are discussed, particularly the relation of style to design, suggesting that there is the possibility for a material language that both the discourses of gardening and landscape architecture shares that could negotiate this breach. A model or “transactions” between gardener and garden is put forward to begin to get to grips with the particular methods of “working at a remove”, that is, curating conditions rather than designing objects. The paper finally proposes that landscape architecture has to move away from a paranoid engagement with specifiable objects, to one where the designer grooms conditions and sensibilities, and gets out of the office.
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Sugarcane orange rust, caused by Puccinia kuehnii, was once considered a minor disease in the Australian sugar industry. However, in 2000 a new race of the pathogen devastated the high-performing sugarcane cultivar Q124, and caused the industry Aus$150–210 million in yield losses. At the time of the epidemic, very little was known about the genetic and pathogenic diversity of the fungus in Australia and neighbouring sugar industries. DNA sequence data from three rDNA regions were used to determine the genetic relationships between isolates within two P. kuehnii collections. The first collection comprised only recent Australian field isolates and limited sequence variation was detected within this population. In the second study, Australian isolates were compared with isolates from Papua New Guinea, Indonesia, China and historical herbarium collections. Greater sequence variation was detected in this collection and phylogenetic analyses grouped the isolates into three clades. All isolates from commercial cane fields clustered together including the recent Australianfield isolates and the Australian historical isolate from 1898.The other two clades included rust isolates from wild and garden canes in Indonesia and PNG. These rusts appeared morphologically similar to P. kuehnii and could potentially pose a quarantine threat to the Australian sugar industry. The results have revealed greater diversity in sugarcane rusts than previously thought.