Preventive and curative control of poplar rust in nursery

Abstract

The poplar rust is the main disease in the field and nursery conditions in poplar area in Brazil. The main damage caused by this disease is the early defoliation. In this work was assessed curative and preventive control in the field and also the inhibitory effect to the spores germination of some fungicides in vitro. Two experiments were carried out in poplar nursery using the most susceptible clone (“Latorre”) using four blocs and six treatments: acibenzolar-S-methyl, quaternary ammonium, mancozeb, tebuconazole + azoxystrobin and control, during 2003/04 e 2004/05. The disease assessment was from December to April by incidence, severity and defoliation. Also was assessed the height and diameter of breast height (DBH) on the end of the experiment. In vitro was considered potencial to reduce spores germination at 1, 10 e 10 g.L^-1. The mixture of azostrobina and tebuconazole reduced 98,4 % of uredospores germination. The products with tebuconazole were efficient to preventive and curative control of the disease and also reduced the defoliation on 30 % but no influence was observed on the DBH. The defoliation was explained by the disease severity with 0,69 of determinant coefficient (R²).