Vascular streak dieback (VSD), caused by the basidiomycete Ceratobasidium theobromae (syn. Oncobasidium theobromae), is a serious disease of cocoa in Southeast Asia and Melanesia. In the last decade, in many cocoa growing areas in Malaysia and Indonesia, the impact of this disease has increased considerably. In the same period, symptoms of the disease have become dominated by necrotic lesions on infected leaves, in contrast to chlorotic symptoms, characterised by yellowing of the leaf with a typical pattern of remnant green islands, which were formerly ubiquitous. Amplification of basidiomycete ITS and LSU sequences in DNA extracts of VSD-infected plant tissues collected from Sulawesi, Indonesia, and Kerala, India, showing chlorotic symptoms matched previous GenBank accessions (99%). However, neither isolation of an axenic culture nor direct PCR amplification from necrotic leaf tissues was successful. Nevertheless, basidiocarps collected from branches with either necrotic or chlorotic VSD symptom in Sulawesi produced basidiospores and basidia with similar dimensions to those previously documented for C. theobromae suggesting that the same pathogen is associated with both symptoms. Incidence of necrotic symptoms was correlated with disease severity in branches. VSD monitored in a range of resistant and susceptible cocoa clones showed rankings for disease incidence and severity that were consistent for three seasons, confirming that disease resistance was maintained despite the prevalence of necrotic leaf symptoms. A lower proportion of symptomatic leaves on branches 5 months after early symptoms were observed in the resistant Malaysian clone PBC123 (32.6%) compared to the more susceptible M04 (46.9%). Clones common to trials in three different districts in Sulawesi showed a consistently high level of resistance to VSD, including PBC123 and two local selections, M05 and GeniJ.

由担子菌Ceratobasidium theobromae （同义词Oncobasidium theobromae）引起的血管条纹枯死 (VSD))，是一种严重的可可病，在东南亚和美拉尼西亚出现。在过去十年中，在马来西亚和印度尼西亚的许多可可种植区，这种疾病的影响已大大增加。在同一时期，该病的症状以受感染叶片上的坏死病变为主，与褪绿症状相反，其特征是叶片变黄并带有典型的残留绿岛图案，这些图案以前无处不在。从印度尼西亚苏拉威西岛和印度喀拉拉邦采集的受 VSD 感染的植物组织 DNA 提取物中担子菌 ITS 和 LSU 序列的扩增，显示褪绿症状与之前的 GenBank 加入（99%）相匹配。然而，从坏死叶组织中分离无菌培养物或直接 PCR 扩增均未成功。尽管如此，C. theobromae表明相同的病原体与两种症状有关。坏死症状的发生率与分支的疾病严重程度相关。在一系列抗性和易感可可克隆中监测的 VSD 显示，三个季节的发病率和严重程度排名一致，证实尽管存在坏死叶症状，但仍保持抗病性。与更易感的 M04 (46.9%) 相比，在抗性马来西亚克隆 PBC123 (32.6%) 中观察到早期症状 5 个月后树枝上有症状的叶子比例较低。在苏拉威西岛三个不同地区的试验中常见的克隆对 VSD 表现出一贯的高水平抗性，包括 PBC123 和两个本地选择 M05 和 GeniJ。