Poplar rust (Melampsora medusae Thuem.) causes serious damage in the plant nursery and its control is essential to obtain good quality seedlings. This work aimed at: i) testing the efficiency of contact fungicides (mancozebe, cartap and copper oxichloride) and systemic fungicides (triadimenol, tebuconazole and difenoconazole) for poplar rust control; ii) comparing evaluation methods to discriminate the efficiency among the treatments; iii) relating defoliation and disease data and iv) verify the influence of rust control under growth tree parameters. The experiment was conducted in São Mateus do Sul, PR and arranged in a completely randomized design with 10 treatments (check, triadimenol, mancozebe, tebuconazole, difenoconazole, cartap, copper oxichloride, triadimenol-mancozebe, tebuconazole-mancozebe and triadimenol applied at double the interval of the previous ones) and 11 repetitions. The experimental plots were 10 m wide with 4 planting rows (space between the lines was 2.5 and between the plants, 0.50 m), totaling 110 plots with the Latorre clone. The following aspects were evaluated during two consecutive cycles: number of pustules per half leaf; visual percentage of the disease; severity per plot; visual percentage of defoliation, diameter at breast height and plant height at the end of the experiment. The systemic products (triadimenol, tebuconazole and difenoconazole) applied alone or interpolated with mancozebe were efficient in controlling the disease, reducing both the number of leaf pustules and defoliation, resulting in a significant gain in the final plant volume. Mancozebe applied alone also reduced epidemics and increased tree volume in 42%. The cupric product made the volume increase in 27%. The evaluation methods used showed differences among the treatments and there was a correlation between the disease and the damage caused to the culture.
Populus spp.; Melampsora medusae; fungicides
