Raitech Ltd, Kununurra, WA 6743, Australia.
Department of Primary Industries and Regional Development, South Perth, WA 6151, Australia.
Virus Res. 2020 May;281:197934. doi: 10.1016/j.virusres.2020.197934. Epub 2020 Mar 19.
The Ord River Irrigation Area (ORIA) produces annual crops during the dry season (April to October), and perennial crops all-year-round, and is located in tropical northwestern Australia. Sandalwood plantations cover 50 % of the ORIA's cropping area. Aphids cause major crop losses through transmission of viruses causing debilitating diseases and direct feeding damage. During 2016-2017, in both dry and wet seasons a total of 3320 leaf samples were collected from diverse types of sites on cultivated and uncultivated land and 1248 (38 %) of them were from aphid-colonized plants. In addition, aphids were found at 236 of 355 sampling sites. The 62 plant species sampled came from 23 families 19 of which contained aphid-colonized species. Aphid hosts included introduced weeds, Australian native plants, and volunteer or planted crop plants. Six aphid species were identified by light microscopy and CO1 gene sequencing, but there was no within species nucleotide sequence diversity. Aphis nerii, Hysteroneura setariae, Rhopalosiphum maidis and Schoutedenia ralumensis each colonized 1-3 plant species from a single plant family. A. craccivora colonized 14 species in five plant families. A. gossypii was the most polyphagous species colonizing 19 species in 11 plant families. A. gossypii, A. craccivora, A. nerii and S. ralumensis were found in both wet and dry seasons. Because of A. craccivora's prevalence and high incidences on understory weeds and host trees, sandalwood plantations were important reservoirs for aphid spread to wild and crop plant hosts growing in cultivated and uncultivated land. Alternative hosts growing in rural bushland, irrigation channel banks, vacant or fallow land, and orchard plantation understories also constituted significant aphid reservoirs. This study provides new knowledge of the ecology of aphid vector species not only in the ORIA but also in tropical northern Australia generally. It represents one of relatively few investigations on aphid ecology in tropical environments worldwide.
澳大利亚西北部的奥里利亚灌溉区（ORIA）在旱季（4 月至 10 月）种植一年生作物，全年种植多年生作物，檀香种植园占地 50%。蚜虫通过传播导致衰弱疾病的病毒和直接取食造成重大作物损失。在 2016-2017 年，在旱季和雨季，总共从种植和未种植土地的不同类型地点采集了 3320 个叶片样本，其中 1248 个（38%）来自受蚜虫侵害的植物。此外，在 355 个采样点中的 236 个发现了蚜虫。采集的 62 种植物来自 23 个科，其中 19 个科含有受蚜虫侵害的物种。蚜虫的寄主包括外来杂草、澳大利亚本地植物、自愿种植的作物和种植的作物。通过光学显微镜和 CO1 基因测序鉴定了 6 种蚜虫，但是没有种内核苷酸序列多样性。桃蚜、禾谷缢管蚜、玉米蚜和 Schoutedenia ralumensis 分别从单个植物科的 1-3 种植物中定殖，Aphis craccivora 从 5 个植物科的 14 种植物中定殖，Aphis gossypii 是最杂食性的物种，从 11 个植物科的 19 种植物中定殖。Aphis gossypii、Aphis craccivora、Aphis nerii 和 Schoutedenia ralumensis 在旱季和雨季均有发现。由于 Aphis craccivora 的普遍性和在林下杂草和寄主树上的高发病率，檀香种植园是蚜虫传播到野生和种植作物寄主的重要蓄水池，这些寄主生长在种植和未种植的土地上。生长在农村丛林、灌溉渠堤、空地或休耕地以及果园种植林下的替代寄主也是重要的蚜虫蓄水池。本研究不仅为 ORIA 地区，而且为澳大利亚北部热带地区蚜虫媒介物种的生态学提供了新知识。这是全球热带环境中为数不多的对蚜虫生态学调查之一。
