Verticillium wilt, caused by Verticillium dahliae is considered the most serious biotic threat to olive trees. The disease is detected in almost all regions where olive is cultivated, and it may cause olive decline and dieback. The aim of this study was to determine the incidence and distribution of Verticillium wilt on olive trees in Istria (Croatia), to identify pathotype groups and race structure of the local V. dahliae population and to determine the susceptibility of Croatian olive cultivars to Verticillium wilt. In a field survey, Verticillium wilt was found to be the most common cause of olive decline, as it was detected in 61% of investigated locations. Out of 78 isolates of potentially pathogenic fungi obtained from olive trees with decline or dieback symptoms, 36% isolates of V. dahliae were determined. Molecular identifications based on PCR with specific primer sets showed that all V. dahliae isolates belonged to the nondefoliating pathotype (ND) and race 1. Olive cultivars Buža, Karbonaca, Istarska Bjelica, Rosinjola and Leccino were selected for susceptibility experiments, performed in a greenhouse, with a mix of three indigenous ND race 1 V. dahliae isolates used as inoculum. Different susceptibilities of local olive cultivars to V. dahliae infection were observed, with cultivar Karbonaca scoring as the most resistant. To the best of our knowledge, this is the first study showing Verticillium wilt as a widespread olive disease in Istria, confirming for the first time in Croatia the presence of a less aggressive, nondefoliating pathotype and race 1.

由大丽轮枝菌引起的黄萎病被认为是对橄榄树最严重的生物威胁。几乎所有种植橄榄的地区都会发现这种疾病，它可能导致橄榄衰退和枯死。本研究的目的是确定伊斯特拉（克罗地亚）橄榄树上黄萎病的发病率和分布，以确定当地大丽花的致病型组和小种结构人口并确定克罗地亚橄榄品种对黄萎病的敏感性。在实地调查中，发现黄萎病是橄榄衰退的最常见原因，因为它在 61% 的调查地点被检测到。在从具有衰退或枯死症状的橄榄树中获得的 78 株潜在致病真菌中，确定了36% 的大丽花分离株。基于 PCR 和特定引物组的分子鉴定表明，所有大丽花分离株都属于非脱叶病型 (ND) 和种族 1。橄榄栽培品种 Buža、Karbonaca、Istarska Bjelica、Rosinjola 和 Leccino 被选作敏感性实验，在温室中进行, 混合了三个土著 ND 种族 1 V. dahliae用作接种物的分离物。观察到当地橄榄品种对大丽花感染的不同敏感性，品种 Karbonaca 得分最高。据我们所知，这是第一项研究表明黄萎病是伊斯特拉半岛普遍存在的橄榄病，首次证实克罗地亚存在一种攻击性较低的非脱叶病型和种族 1。