Isolation trials of bacteria associated to leaf spot collected from various locations in Egypt yielded 39 bacterial isolates. Following purification, the isolated bacteria were identified as Bacillus spp. (15 isolates), Pseudomonas spp. (12 isolates), and Xanthomonas campestris pv. vesicatoria "Xcv" (12 isolates). Both Bacillus spp. and Pseudomonas spp. had the higher frequency, being 38.46 and 30.77%, respectively than Xcv (30.77%). I1, I3, I4, I6, I9, I10, I11, and I12 had a low pathogenicity index exclusively on pepper plants. The antibacterial capabilities of five tested bacteriotoxicants were evaluated against Xcv in vitro. Copper oxychloride had the greatest increase in the inhibitory zone, followed by oxytetracycline then hydrogen peroxide, and clove oil treatments, being 6.32, 5.45, 5.14, and 4.52 mm, respectively. In vivo, all treatments examined outperformed the control treatment in terms of reducing bacterial leaf spot disease evaluation. All evaluated treatments increased total pepper production. Copper-treated control treatment resulted in the greatest increase in total fruit yield (23.68 kg/plot) during two successive growing seasons (2019/2020 and 2020/2021). The oxytetracycline, curcumin, clove oil, and hydrogen peroxide treatments all had a great effect on increasing total fruit yield. The investigated treatments enhanced total phenols content and oxidative enzymes activity in pepper leaves as compared to the treated-copper control and untreated control treatments. Curcumin, followed by clove oil and thenhydrogen peroxide, provided the greatest rise in the determined oxidative enzymes activities in leaves. In terms of vitamin-C increase percentage, all evaluated bacteriotoxicants enhanced vitamin-C content. |
