Abstract Bacterial spot disease caused by Xanthomonas euvesicatoria is one of the major constraints for pepper production in Florida and worldwide. The common prevalence of copper (Cu)-tolerant X. euvesicatoria strains has reduced the efficacy of Cu based bactericides against bacterial spot of pepper. In this study, we evaluated antimicrobial activity of three Cu-based nanocomposites, namely, core-shell Cu (CS–Cu), fixed-quat Cu (FQ-Cu) and mixed-valence Cu (MV-Cu), along with Kocide® 3000, which is a micron size metallic Cu bactericide and is commercially available, both in vitro and in greenhouse trials, against a Cu-tolerant strain of X. euvesicatoria. In repeated in vitro tests, X. euvesicatoria growth was completely inhibited 24 h after exposure of bacterial cells to 500 and 1000 μg/ml of MV-Cu and all concentrations of FQ-Cu and CS-Cu (100, 200, 500, and 1000 μg/ml) treated for 1 h. Micron size copper, even at 1000 μg/ml, had no statistical difference in growth in comparison to the untreated control (P = 0.05; LSD). In the repeated greenhouse experiments, plants treated with all the copper composites exhibited less bacterial spot severity than untreated control and similar or significantly less than Cu-mancozeb (P

中文翻译：

---

铜复合材料对黄单胞菌的抑菌作用

摘要 由 Xanthomonas euvesicatoria 引起的细菌性斑点病是佛罗里达州和世界范围内辣椒生产的主要制约因素之一。铜 (Cu) 耐受性 X.euvesicatoria 菌株的普遍流行降低了基于铜的杀菌剂对辣椒细菌性斑点病的功效。在这项研究中，我们评估了三种铜基纳米复合材料的抗菌活性，即核壳铜 (CS-Cu)、固定季铵铜 (FQ-Cu) 和混合价铜 (MV-Cu)，以及 Kocide ® 3000，这是一种微米尺寸的金属铜杀菌剂，可在体外和温室试验中通过商业途径获得，用于对抗耐铜的 X.euvesicatoria 菌株。在重复的体外测试中，细菌细胞暴露于 500 和 1000 μg/ml MV-Cu 以及所有浓度的 FQ-Cu 和 CS-Cu（100，200、500 和 1000 μg/ml）处理 1 小时。与未处理的对照相比，微米级铜，即使在 1000 微克/毫升时，在生长方面也没有统计学差异（P = 0.05；LSD）。在重复的温室实验中，用所有铜复合物处理的植物表现出的细菌斑点严重程度低于未处理的对照，与铜代森锰锌相似或显着低于（P