Brand, ThomasBeltz, HeinrichEhsen, BjörnAdhikari, UrmilaDaughtrey, MargeryLuster, Douglas G.Kong, PingHong, Chuanxue2023-01-042023-01-042022-07-220191-2917http://hdl.handle.net/10919/113024Two multi-year field trials were conducted to evaluate boxwood cultivars for their susceptibility to the blight pathogens <i>Calonectria pseudonaviculata</i> and <i>C. henricotiae</i> in northern Germany. Fifteen cultivars were included in the first trial from 2007 to 2012, and 46 cultivars in the second trial from 2014 to 2017. Both trials were done in a naturally infested field, supplemented with infected plant tissue added to the soil before planting. Each cultivar had three replicate hedge sections with ten plants per section and they were assessed annually for blight severity expressed as proportion of leaves blighted and fallen. Blight severity varied significantly among years (<i>P</i> < 0.0001) and cultivars (<i>P</i> < 0.05) within each trial. In the first trial, mean severity ranged from 0.03 to 0.11 for the most resistant cultivars and 0.35 to 0.96 for the most susceptible ones. Similarly, in the second trial, mean severity ranged from 0.06 to 0.27 and 0.71 to 0.97 for the most resistant and susceptible cultivars, respectively. 'Suffruticosa' was consistently the most susceptible cultivar, followed by 'Marianne', 'Myosotidifolia', 'Raket' and 'Morris Midget'. 'Herrenhausen' was the most resistant cultivar, followed by <i>B. microphylla</i> var. <i>japonica</i>, <i>B. microphylla</i> var. <i>koreana</i>, 'Green Mound', 'Faulkner', and 'Winter Beauty'. This study provides field data showing the performance of boxwood cultivars under different levels of disease pressure in an area where <i>C. henricotiae</i> was dominant. This knowledge will help boxwood growers and gardeners to choose less susceptible cultivars and help plant breeders to select for disease resistance.application/pdfenIn CopyrightCalonectria henricotiaeCalonectria pseudonaviculataCylindrocladium buxicolaBoxwood blightblight mitigationcultivar evaluationresistanceArticle - Refereed2022-12-31https://doi.org/10.1094/pdis-05-22-1102-reHong, Chuanxue [0000-0001-7389-5157]358695841943-7692