Chemical products induce resistance to Xanthomonas perforans in tomato

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

The bacterial spot of tomato, caused by Xanthomonas 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.L1), fluazinam (0.25 g.L1), pyraclostrobin (0.08 g.L1), pyraclostrobin + methiran (0.02 g.L1 + 2.2 g.L1), copper oxychloride (1.50 g.L1), mancozeb + copper oxychloride (0.88 g.L1 + 0.60 g.L1), and oxytetracycline (0.40 g.L1)) on control of bacterial spot. Tomatoes Santa Clara and Gisele cultivars were pulverized 3 days before inoculation with Xanthomonas perforans. The production of enzymes associated with resistance induction (peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, -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 -1,3-glucanase in the Santa Clara cultivar.

1. Solanum lycopersicum
2. control
3. enzymes
4. bacterial spot