NEONICOTINOIDES COMO INDUTORES DE RESISTÊNCIA EM TOMATEIRO CONTRA A MANCHA BACTERIANA

Abstract

The tomato bacterial spot is one of the most important diseases at the crop because it may cause the reduction in productivity due to the destruction of leaf area, this way reducing the photosynthetic rate of the plant and therefore causing loss of flowers and fruits in development. The use of inductors of resistance has been one of the ways of disease management in the commercial areas. This study aimed to measure the tomato plant resistance induction (cv. AP 533) through the use of neonicotinoid insecticides. The experiment was conducted in a vegetation house at the Instituto Federal Goiano Campus Morrinhos. We evaluated the insecticide imidacloprid (IMD) and tiamethoxan (TMT), which were compared with acibenzolar-s-methyl (ASM), a resistance inductor registered on the management of tomato bacterial spot, and with a control treatment where was applied water. A number of two tests were conducted, the first being evaluated the concentrations of 40, 217.5 and 200 g / L ASM, IMD e TMT and as well as the reduction of these at 10 and 1%. In this assay, there was phytotoxicity by using IMD concentrations 217.5 and 21.7 g / L and the concentration of TMT and 200 g / L. In other concentrations it were observed a reduction of disease severity compared to the control treatment, similar to that were observed with the use of ASM. In the second trial were removed the higher concentration of each product, and It were evaluated in a dilution of 1: 0, 1: 100 and 1: 1000. There was a reduction of disease severity in all concentrations evaluated the active ingredients compared to control. It evaluated the direct effect of insecticides on the pathogen (Xanthomonas perforans) by diffusion disc test. At all of the concentrations tested, it was observed bacterial growth inhibition by the active principles IMD or TMT. This result supports the hypothesis that these products can induce the resistance in plants against a plant pathogenic bacteria.