Efficacy of compost, bioagents and some commercial biocides individually or in combination for controlling tomato sclerotinia rot caused by Sclerotinia sclerotiorum (Lib.) de Bary under greenhouse and field conditions were studied. Results indicated that Trichoderma album and Bacillus subtilis were the most effective bioagents in inhibiting mycelial growth of S. sclerotiorum in vitro. All treatments significantly reduced disease incidence and severity of tomato white rot disease compared with untreated control. However, T. album and Pseudomonas fluorescens combined with compost reduced the disease incidence and disease severity from 100 and 77.40 in control to 11.1 & 1.5% and 11.1 & 2.5%, respectively, under greenhouse conditions. The integrated T. album, P. fluorescens and Bio-Zeid with compost recorded the highest increase of fresh weight and dry weight of shoots and roots compared with individual treatments and control. Under field conditions, adding compost to the soil pre-transplanting decreased the percentage of infection and increased yield of tomato plants compared with other treatments with compost. In this respect, the integration between T. album + B. subtilis + Ps. fluorescens and compost was the most effective treatment for reduced the disease incidence and disease severity. As well as, this treatment increased the fruit weight per plant. On the side, all treatments increased the phenols and flavonoids content in tomato plants. The highest increase in the total phenols and flavonoids contents were recorded with T. album, P. fluorescens and Bio-Zeid combined with compost. Also, all treatments increased peroxidase (PO), polyphenoloxidase (PPO), chitinase and β-1, 3-glucanase activities in treated tomato plants. It could be concluded, the combination between compost, bioagents and some commercial biocides might be useful as an useful tool for controlling tomato sclerotinia disease under greenhouses and field conditions.
Treating pepper plants with phenolic compounds i.e. pyrogallol, catechol, caffeic, tannic and cinnamic significantly decreased bacterial spot disease of pepper plants. Treated pepper leaves at 2 days before inoculation with Xanthomonas vesicatoria was more effective in reducing disease incidence and severity than inoculated plants with X. vesicatoria at once with spraying phenolic compounds. Spraying pepper leaves 2 days with pyrogallol before inoculation, exhibited that, pyrogallol was the most effective treatment which reduced disease incidence and disease severity by 85.71 and 91.99% respectively followed by catechol and cinnamic which were reduced disease incidence with 80.96 and 76.19% and severity by89.33 and 86.67% respectively. As for biochemical changes, the obtained results showed that, PO, PPO, PAL, chitinase and β-1,3-glucanase activities increased as a result of spraying pepper plants with the tested phenolic compounds compared to untreated control. As well as, all treatments led to an induction of PO isoenzymes in treated pepper plants. The data also illustrated that two unique bands were detected and specific to Pyrogallol 2 and Pyrogallol 3 and one unique band was detected as affected to Pyrogallol 1. Polyacrylamide gel electrophoresis of protein showed that 15 protein bands with molecular weights ranging from 122 to 25 kDa are contained in pepper plants. New protein bands expressed as a result of treating pepper plants with phenolic inducers. Four new bands found between 25 and 56 Kda and a fifth band at 84 Kda.
Wheat (Triticum aestivum L) is the most important cereal crop worldwide. It is responsible for providing more than 40% of humans with their nutritional requirements from carbohydrates and other essential nutrients. Unfortunately, its attacked by different various air and soil borne pathogens which resulted in massive losses in both yield quantity and quality. In Egypt, wheat is not only just a nutritional cereal crop, but it is considered the food security key. There is a huge gap between the wheat grain production and national consumption levels. Therefore, saving each grain from wheat production deemed urgent need. Using resistant cultivars against important invaded pathogens is considering one of the most effective and relevant techniques that can be used in the battle between plant pathologists and hazardous pathogen i.e. Puccinia triticina and Fusarium pseudograminiarum. In the current study, the resistance potential of 29 different Egyptian wheat cultivars was assessed against 3 leaf rust races and crown rot disease individually. The results showed that the tolerance potential of the tested cultivars toward either P. triticina or F. pseudograminiarum was varied significantly. Also, the relation between the incidences of the two diseases was estimated. Results indicating that there are a positive correlation between incidence of leaf rust and incidence of crown rot diseases. These findings could lead to designing special models which can be used in the prediction of the incidence by one of the two pathogens when the other attacks the wheat plants.
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