SENSIBILIDADE DE Xanthomonas euvesicatoria pv. perforans A FUNGICIDA A BASE DE PIDIFLUMETOFEN E DIFENOCONAZOL

Abstract

The goal of the study was to evaluate the direct effects of products based on hydroxide of copper (HC), acibenzolar-s-methyl (ASM), difenoconazole (DIF), and pydiflumetofen + difeconazole (PIDIF) on X.euvesicatoria pv. perforans "in vitro". There were 3 experiments conducted in a completely randomized design. The first one, on a scheme 3x5+1, with 3 products (PIDIF, ASM and HC), 5 doses, and 1 control treatment without fungicide, with 3 repetitions for each treatment. In the second one, 4x5+1, the 4 products (PIDIF, ASM, HC, and DIF), 5 doses and 1 control, with 5 repetitions for each treatment. In the third experiment, was tested only 2 products and 5 doses (PIDIF and DIF), and the other 2 products only in one dose (ASM using the recommended dose of 25g/300L and HC 300g/300mL), with 5 repetitions for each treatment. The 5 doses were divided into 1 dose of recommended concentration (500mL, 25g, 3000g, and 73mL/300L for PIDIF, ASM, HC, and DIF, respectively), 5 and 10 times higher than recommended, 5 and 10 times lower than recommended. The products were dosed and added to test tubes containing 10 mL of bacterial suspension then taken to an incubator at 120 rpm at 28°C for 24 hours. Therefore, 100 µl aliquots were spread on agar medium nutrient in a Petri dish then taken to the B.O.D greenhouse at 28ºC, until the colonies grow. The first experiment served for comparative ends, indicating the presence or absence of bacteria. In the second experiment, the doses 5 and 10 times higher than recommended of PIDIF inhibited the growth of colonies, as well as all doses of HC. The other doses of PIDIF and all doses of DIF and ASM did not differ from the control. However, in the third experiment, all the doses of PIDIF inhibited the growth of colonies, as well as the unique dose of hydroxide of copper (0,3kg/ha). For the treatments based on difenoconazole and acibenzolar-s-methyl, there was no statistical difference between these and the control.