A series of independent trials were conducted to evaluate the use of UV-C radiation for controlling Xanthomonas campestris pv. vitians (Xcv), the causative agent of bacterial leaf spot in lettuce, and to assess the impact of this treatment on lettuce yield. The first trial involved repeated applications of a pre-established hormetic dose of UV-C (0.4 kJ/m²), for a total dose of 1.6 kJ/m², which represented a single treatment cycle. Lettuce plants were inoculated with a virulent strain of Xcv 48 h after this treatment cycle. The second trial, which took place after Xcv inoculation, involved additional UV-C treatment cycles (0.5, 1.0 and 1.75 cycles), corresponding to total doses of 2.4, 3.2 and 4.4 kJ/m² respectively. In the third trial, three weekly UV-C treatments were given at 48 h intervals using the standard 0.4 kJ/m² dose, beginning the third week after seeding and continuing until the lettuce reached the commercial stage and was harvested. By the time the mature lettuce plants were harvested, they had undergone five treatment cycles, representing a total dose of 8 kJ/m². A single UV-C treatment cycle resulted in a 90 %, 30 % or 10 % reduction in the susceptibility of the growing lettuce plants to Xcv compared with the control group, depending on when symptoms were evaluated. The application of additional treatment cycles (0.5, 1.0 and 1.75 cycles) resulted in a reduction of 30 %, 45 % and 50 % in susceptibility, respectively, in the treated lettuce plants relative to the controls. The fresh yield of lettuce treated with 2.75 cycles of UV-C (4.4 kJ/m²) was similar to that of the control lettuce; this treatment also resulted in a significant decrease (20 %) in core length, an agronomic trait associated with increased yield when lettuce is processed as fresh-cut ready-to-eat product. UV-C-treated lettuce had a significantly greater dry matter content and higher total mineral concentrations than the control lettuce. These results indicate that repeated preharvest UV-C treatments (0.4 kJ/m²) improve the tolerance of lettuce to Xcv without negative effects.

进行了一系列的独立试验，以评估使用UV-C辐射控制樟脑黄单胞菌pv的使用。vitians（Xcv）是莴苣中细菌性叶斑的病原体，并评估该处理对莴苣产量的影响。第一次试验涉及重复应用预先确定的剂量的UV-C（0.4 kJ / m ²），总剂量为1.6 kJ / m ²，代表一个治疗周期。在该处理周期后48小时，用Xcv的强毒株接种莴苣植物。第二次审判是在Xcv之后进行的接种涉及额外的UV-C处理周期（0.5、1.0和1.75个周期），分别对应于2.4、3.2和4.4 kJ / m ^2的总剂量。在第三次试验中，从种子播种后的第三周开始一直持续到生菜达到商业化阶段并收获为止，以标准的0.4 kJ / m ²剂量每48小时间隔进行三周的UV-C处理。到成熟的莴苣植物收获时，它们经历了五个处理周期，总剂量为8 kJ / m ²。单个UV-C处理周期可使生菜植物对Xcv的敏感性降低90％，30％或10％与对照组相比，取决于何时评估症状。相对于对照，施加额外的处理周期（0.5、1.0和1.75个周期）分别使处理过的生菜植株的药敏性降低30％，45％和50％。用2.75个UV-C循环（4.4 kJ / m ²）处理的生菜的新鲜产量与对照生菜相似。这种处理还导致核心长度显着减少（20％），这是一种将莴苣加工为即食即食产品时与提高产量相关的农艺性状。与对照生菜相比，经UV-C处理的生菜具有明显更高的干物质含量和更高的总矿物质浓度。这些结果表明，收获前反复进行UV-C处理（0.4 kJ / m ²）提高莴苣对Xcv的耐受性，而不会产生负面影响。