The ascomycete fungus Geosmithia morbida (GM) and the walnut twig beetle (WTB), Pityophthorus juglandis, constitute a recently discovered fungal–insect complex responsible for the harmful Thousand Canker Disease (TCD) in walnut trees. Key aspects of the epidemiology and ecology of the fungus and its insect vector were investigated in a disease outbreak found in central Italy, currently the southernmost introduction area of TCD on the Old Continent. Walnut trees with symptoms of crown dieback and epicormic branching with beetle galleries were sampled for pathogen isolation, while funnel traps were used to catch beetles and obtain adult flight curves. Growth-temperature relationships were determined for the fungus; optimum growth temperature for GM was 25°C, but it thrived up to 37°C. The phloem-boring bark beetle showed a longer flight period than in northern Italy. The beetle haplotype identified in Tuscany (H1) differed from haplotypes H2 and H21 found in northern Italy, suggesting possible multiple anthropogenic introductions. The substantial high temperature tolerance shown by the two organisms suggests they will not be constrained by the high temperatures of warmer areas. As a consequence, the impact of TCD in southern Europe, where the native Juglans regia is widely cultivated for its nuts and wood, would potentially be disastrous to local economies. In fact, although J. regia is not considered as susceptible as J. nigra, it can nevertheless be attacked in conditions of high bark beetle population density, a harbinger of high fungus’ propagule pressure.

子囊真菌莫比达（GM）和胡桃木甲虫（WTB），Pityophthorus juglandis，是一种最近发现的真菌-昆虫复合物，其引起核桃树中的有害千株溃疡病（TCD）。在意大利中部（目前是旧大陆上TCD最南端的引入地区）发现的疾病暴发中，对真菌及其昆虫媒介的流行病学和生态学的关键方面进行了调查。取核桃树冠冠枯死和表皮科分支与甲虫画廊分离的核桃树进行病原体分离，同时使用漏斗诱集器捕获甲虫并获得成年飞行曲线。确定了真菌的生长温度关系。GM的最佳生长温度为25°C，但最高达到37°C。韧皮部生的树皮甲虫的飞行时间比意大利北部更长。托斯卡纳（H1）中鉴定出的甲虫单倍型与意大利北部发现的单倍型H2和H21不同，这表明可能有多次人为引入。两种生物体显示出显着的高温耐受性，表明它们不会受到温暖地区高温的限制。结果，TCD在南欧的影响胡桃核桃因其坚果和木材而被广泛种植，对当地经济可能造成灾难性影响。实际上，尽管雷格氏菌不像黑缘病菌那样易感，但仍然可以在树皮甲虫种群密度高，真菌繁殖力高的预兆下攻击它。