Control of Bacterial Spot of Tomato and Activation of Enzymes Related to Resistance by Chemicals Under Field Conditions

Abstract

The control of tomato bacterial spot by the application of chemicals was evaluated on field condition during two trials. Thirty days after transplanting and every 14 days the tomato plants PA-529 hybrid were sprayed with acibenzolar-S-methyl (2.5 g·100) and water (control), totaling five applications during the crop cycle. Forty days after transplanting, the plants were inoculated with a Xanthomonas perforans isolate (10 7 UFC·mL -1 ), disease severity was assessed (10, 19, 29, and 36 days after inoculation), and the area under the disease progress curve was calculated. All chemicals controlled the disease, but better results for total mass and number of fruit was obtained for fluazinam, pyraclostrobin, pyraclostrobin + metiram, copper oxychloride, and mancozeb + copper oxychloride in the first trial, and pyraclostrobin and pyraclostrobin + metiram in the second trial. The average fruit weight, °Brix, pH and total acidity were not affected by the application of the chemicals. The enzymatic activity of the polyphenol oxidase and peroxidase was higher in the first trial, but in the second, only the polyphenoloxidase had the highest activity in the treatments with acibenzolar-S-methyl, pyraclostrobin, and pyraclostrobin + metiram on tomato leaves. Products containing pyraclostrobin increased the activity of some enzymes without reducing the productivity.

Evaluation of Equisetum arvense (Horsetail Macerate) as a Copper Substitute for Pathogen Management in Field-Grown Organic Tomato and Durum Wheat Cultivations

“…To the best of our knowledge, a negative effect of Cu-based fungicide treatments on tomato Brix values in organic farming has not been reported previously. In a previous report on tomato, comparing the untreated control and various Cu-fungicides, the Brix values of the fruit were unaffected by the Cu treatments and comparable to the control [33]. Further research would be required to understand the effect of the Cu-based treatments on Brix values.…”

Biotechnological Control Methods Against Phytopathogenic Bacteria in Tomatoes

“…The use of bactericides based on copper in combination with fungicides, ethylenebis-dithionate or MANCOZEB caused an increase in the level of control of even copper-tolerant populations of pathogens. The inductor of plant resistance acibenzolar-S-methyl (CGA-245704 or Actigard) ensured the formation of low indicators of control of the distribution of tomato black bacterial spotting and bacterial mottle (Itako et al, 2014).…”

“…In the field (Itako et al, 2014) it was evaluated the effectiveness of acibenzolar-Smethyl, fluosines, pyraclostrobine, copper oxychloride, MANCOZEB/ сopper oxychloride and pyraclostrobine/metiram for the control of tomato black bacterial spot. In 40 days after transplantation, the plants were inoculated with X. perforans (10 7 CFU/ml) in order to assess the degree of development of the disease.…”

Foliar Application of the Fungicide Pyraclostrobin Reduced Bacterial Spot Disease of Pepper

“…axonopodis pv. phaseoli) Pyraclostrobin metiram acibenzolar-S-methyl (Itako , 2014;Vigo , 2012). Pyraclostrobion PR MAPKs (Herms , 2002;Skandalis , 2016;Udayashankar , 2012…”