Influence of Fusarium spp. Inoculation and shading levels in the erva-mate growth and development

Abstract

A erva-mate ( Ilex paraguariensis A. St.-Hil.) \ue9 uma esp\ue9cie amplamente cultivada no sul do Brasil e pa\uedses vizinhos. Suas folhas e galhos finos, preparados segundo m\ue9todo apropriado, fornecem o mate ou chimarr\ue3o, o mais popular ch\ue1 consumido no Brasil e exportado para todo o mundo. Com o aumento da \ue1rea plantada, sobretudo na \ufaltima d\ue9cada, os problemas fitossanit\ue1rios causados por pragas e doen\ue7as aumentaram e, dentre estes, a podrid\ue3o-de-ra\uedzes vem se tornando um dos principais. A doen\ue7a \ue9 causada por Fusarium spp. e provoca s\ue9rios danos decorrentes da destrui\ue7\ue3o do sistema radicular, ocasionando, nos casos mais graves, morte da planta. A erva-mate \ue9 uma esp\ue9cie que habita o sub-bosque da mata e o cultivo de forma homog\ueanea a pleno sol pode ser um fator estressante ocasionando menor crescimento e desenvolvimento e tamb\ue9m torn\ue1-la mais suscept\uedvel \ue0 podrid\ue3o-de-ra\uedzes. Assim, foram instalados experimentos na \ue1rea do Viveiro Florestal pertencente ao Departamento de Ci\ueancias Florestais da Universidade Federal de Santa Maria com o objetivo de confirmar tais hip\uf3teses. O experimento foi desenvolvido em um esquema fatorial (2 x 5), composto pela inocula\ue7\ue3o de Fusarium spp. e por n\uedveis de sombreamento. Foi observado que plantas submetidas aos menores n\uedveis de sombreamento ou a pleno sol tiveram seu desenvolvimento prejudicado e ficaram mais suscet\uedveis \ue0 doen\ue7a. As plantas inoculadas com Fusarium spp. tiveram menor desenvolvimento em compara\ue7\ue3o com as n\ue3o inoculadas, especialmente nos menores n\uedveis de sombreamento.The erva-mate ( Ilex paraguariensis A. St.-Hil.) 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 \u201cchimarr\ue3o\u201d, 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