Perspectiva de utilização de Prospodium appendiculatum (Wint.) Arth. (Uredinales: Pucciniaceae) no controle biológico de Tecoma stans (L.) Juss. ex Kunth (Bignoniaceae)

Abstract

The specie Tecoma stans is present in the hole Brazil, like an ornamental plant because it has yellow flowers, intensive budding and has a great similarity with the ipês trees and also like a weed in the south Brazil. In the Rio Grande do Sul State this plant is frequently associate to the edge of the highways and roads, and in the nature forest also. In Santa Catarina State the plant is associate like an ornamental, except in a small area near to Concordia city, where the T. stans show a little infestation on the roads edge. In the State of Paraná the principal infestation area of T. stans is located in the north region of the state, from Londrina city region until the border with São Paulo State. In these areas the infestation is in the edges of highways and roads and mainly in pasture areas. In Paraná 50.000 hectares of pastures are invaded by T. stans and from these, 15.000 hectares are totally unproductive (Kranz; Passini, 1997). An example of this plant effectiveness in to attack susceptible areas becoming them a pastures potential invader agent, degraded areas (border of roads) and native forests. The main propose of this project was to study to the biological control of T. stans in the South Brazil, mainly in Rio Grande do Sul and Paraná States. It was selected the fungus Prospodium appendiculatum known like “yellow rust”. This fungus has important characteristics like high specificity and widely distribution in the South Brazil. Three sampling areas with high T. stans infestation were selected to evaluation: two in Parana and one in Rio Grande do Sul states. To evaluate these areas, sample units were installed with 100 square meters each in the period of May to November 2003, in a total of 16 sample units in the three selected areas. The evaluations were done with a field planilha where many parameters were located. It was evaluated 5.572 sprouts in 188 plants of T. stans. The infections occurrence beginning on May in Paraná State and June in Rio Grande do Sul State. In Paraná State, 58% of the sprouts showed infection and 52% showed galls. In Rio Grande do Sul, 24,2% of the sprouts showed infection and 21% showed galls. The results to the north of Paraná region, were promising to the intensity of infections and galls presence. None interferences in the natural pathogen presence was done. These analysis show that this fungus must be studied, mainly because that the obtained data are from its natural occurrence.