Periódicos Brasileiros em Medicina Veterinária e Zootecnia

p. 701-706

Chemical products induce resistance to Xanthomonas perforans in tomato

Itako, Adriana TerumiTolentino Júnior, João BatistaSilva Júnior, Tadeu Antônio Fernandes daSoman, José MarceloMaringoni, Antonio Carlos

<p>The bacterial spot of tomato, caused by <italic>Xanthomonas</italic> spp., is a very important disease, especially in the hot and humid periods of the year. The chemical control of the disease has not been very effective for a number of reasons. This study aimed to evaluate, under greenhouse conditions, the efficacy of leaf-spraying chemicals (acibenzolar-S-methyl (ASM) (0.025 g.L<sup>−1</sup>), fluazinam (0.25 g.L<sup>−1</sup>), pyraclostrobin (0.08 g.L<sup>−1</sup>), pyraclostrobin + methiran (0.02 g.L<sup>−1</sup> + 2.2 g.L<sup>−1</sup>), copper oxychloride (1.50 g.L<sup>−1</sup>), mancozeb + copper oxychloride (0.88 g.L<sup>−1</sup> + 0.60 g.L<sup>−1</sup>), and oxytetracycline (0.40 g.L<sup>−1</sup>)) on control of bacterial spot. Tomatoes Santa Clara and Gisele cultivars were pulverized 3 days before inoculation with <italic>Xanthomonas perforans.</italic> The production of enzymes associated with resistance induction (peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, and protease) was quantified from leaf samples collected 24 hours before and 24 hours after chemical spraying and at 1, 2, 4, 6, and 8 days after bacterial inoculation. All products tested controlled bacterial spot, but only ASM, pyraclostrobin, and pyraclostrobin + metiram increased the production of peroxidase in the leaves of the two tomato cultivars, and increased the production of polyphenol oxidase and β-1,3-glucanase in the Santa Clara cultivar.</p>.(AU)

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