The giant willow aphid (Tuberolachnus salignus) is a large stem-feeding insect which forms dense colonies on infested plants. Since T. salignus is a new invasive species in New Zealand, we have a poor understanding of the plant chemical responses to aphid infestation. This study aimed to characterize the volatile organic compounds (VOCs) emissions of fifteen different willow species and hybrids growing in New Zealand, and to evaluate changes in response to T. salignus attack in a field trial. Volatiles were collected using a headspace sampling technique and analysed using gas chromatography-mass spectrometry (GC-MS). We found high variability in the volatile profiles of different species and hybrids, with (Z)-3-hexenyl acetate and (E)-β-ocimene being the only common components to all blends. Taxonomically related plants showed an overlapping pattern of VOC emission, and there seemed to be a clear separation between shrub and tree willows. Responses to aphid infestation were variable, with only four species/hybrids showing changes in their total VOC emission, or that of at least one class of VOCs. A weak positive correlation between aphid population estimates and VOC emissions suggests that responses are species-specific and not infestation-dependent. These results reveal useful information about the interaction between T. salignus and its potential host plants for biological control and pest management purposes.

中文翻译：

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15种柳树和杂种的挥发性概况及其对巨大柳蚜侵染的响应

巨大的柳蚜（Tuberolachnus salignus）是一种大型的以茎为食的昆虫，在受感染的植物上形成密集的菌落。由于刺线虫是新西兰的一种新入侵种，因此我们对植物对蚜虫侵袭的化学反应了解甚少。这项研究旨在表征在新西兰生长的15种不同的柳树品种和杂种的挥发性有机化合物（VOC）排放，并在田间试验中评估对线虫侵袭反应的变化。使用顶空进样技术收集挥发物，并使用气相色谱-质谱（GC-MS）分析。我们发现（Z）-3-己烯基乙酸酯和（（E）-β-罗勒烯是所有混合物的唯一常见组分。与分类学相关的植物表现出VOC排放的重叠模式，灌木和柳树之间似乎存在明显的分离。对蚜虫侵害的反应是可变的，只有四种/杂种显示出其总VOC排放或至少一类VOC的变化。蚜虫种群估计数与VOC排放量之间的弱正相关表明，响应是特定于物种的，而不是依赖于侵染的。这些结果揭示了有益的信息，有关刺参及其潜在寄主植物之间的相互作用，以进行生物防治和有害生物管理。