An experiment was conducted to study the efficiency of the dosages of 1; 2.5 and 5 g/plant, of the fungicide ridomil 50 gr (metalaxyl, 50 g/kg), in only one application in the soil, compared with the dosage of 400 g/100 liters of water, of the folio (metalaxyl + chlorothalonil, 80 + 400 g/kg) and of the ridomil mancozeb br (metalaxyl + mancozeb, 80 + 640 g/kg), in ten pulverizations for the control of the late blight of the tomato cv. Santa Clara. The experiments were set up in a complete randomized design, with six treatments and four replications. The percentage of the damaged foliage area caused by late blight was of 2.75% in the treatment with folio; 7.25% with ridomil mancozeb br; 18.25, 18.50 and 24.25% with the increasig dosages of the ridomil 50 gr, and, 34.25% in the control treatment. The production of commercially acceptable fruits for ten tomato plants were evaluated in each experimental plot, during four weeks after ninety days of the transplant to field. The yield was 10.26 kg for the treatment with folio; 9.10 kg for the ridomil mancozeb br; 2.07, 1.86 and 1.74 kg for the increasing dosages of the ridomil 50 gr, while the control treatment was 1.58 kg. Treatments with folio and ridomil mancozeb br gave better results in controlling late blight than ridomil 50 gr.
Lycopersicon esculentum; Phytophthora infestans; chemical control; metalaxyl
