Alemu Tameru, Hamacher J, Dehne H W
Institute for Plant Diseases, University of Bonn, Nussallee 9, 53115 Bonn, Germany.
Meded Rijksuniv Gent Fak Landbouwkd Toegep Biol Wet. 2002;67(2):283-9.
Hot pepper (Capsicum annuum. L.) is a traditionally and economically important spice crop in Ethiopia. Chronic infection with viruses is reported as major constraint, that often force farmers to ban its production. However, epidemiological studies on these viruses are lacking in the country. Knowledge of the weed flora as virus reservoir is essential to reduce the spread of plant viruses. The potential role of some frequently and abundantly occurring weed species as host plants for Capsicum viruses was therefore investigated. Surveys were conducted during the 2000/2001 cropping- and off-season. Samples of various weed species revealing virus symptoms were collected from different districts. Collection was done from inside and at the border of pepper cropped and fallow fields. It was also performed along road sides and irrigation channels. The identity of the collected isolates was established based on serology, electron microscopy and host range studies. Moreover, seeds were collected from natural populations of the most prevalent weeds, namely Datura stramonium and Nicandra physalodes. They were grown under glass house conditions and tested for their ability to host viruses. To verify their role further, healthy seedlings from these weeds were artificially inoculated with all viruses isolated from weeds and Capsicum leaf samples. Natural infection of different Potyviruses with an average incidence of 33% in the weed samples were the most dominant. In addition, the occurrence of Cucumber mosaic virus, Tomato mosaic virus and Potato virus X in these weeds was demonstrated. However, none of the isolated viruses was found to be seed borne in the tested weed species and pepper crop (var.Mrkofanna) under glass house conditions. Recently, there was an explosion in population size of some solanaceous weeds, particularly Datura and Nicandra species in the area. The presence of infected weeds throughout the year means, that they are an important reservoir and source for secondary spread. It is suggested therefore, that a rigorous weed control is an important step to reduce the incidence of viruses infecting Capsicum in the area.
辣椒（Capsicum annuum. L.）是埃塞俄比亚一种具有传统和经济重要性的香料作物。据报道，病毒的慢性感染是主要制约因素，这常常迫使农民禁止种植辣椒。然而，该国缺乏对这些病毒的流行病学研究。了解作为病毒宿主的杂草群落对于减少植物病毒的传播至关重要。因此，研究了一些常见且大量出现的杂草物种作为辣椒病毒宿主植物的潜在作用。在2000/2001种植季和非种植季进行了调查。从不同地区收集了显示病毒症状的各种杂草样本。采集工作在辣椒种植田和休耕田内部及边界进行，也在路边和灌溉渠道沿线进行。基于血清学、电子显微镜和寄主范围研究确定了所收集分离物的身份。此外，从最常见的杂草即曼陀罗（Datura stramonium）和假酸浆（Nicandra physalodes）的自然种群中收集了种子。将它们在温室条件下种植，并测试其携带病毒的能力。为进一步验证它们的作用，用从杂草和辣椒叶片样本中分离出的所有病毒对这些杂草的健康幼苗进行人工接种。杂草样本中不同马铃薯Y病毒的自然感染最为普遍，平均发病率为33%。此外，还证实了这些杂草中黄瓜花叶病毒、番茄花叶病毒和马铃薯X病毒的存在。然而，在温室条件下，在所测试的杂草物种和辣椒作物（品种Mrkofanna）中均未发现分离出的病毒是种传的。最近，该地区一些茄科杂草的种群数量激增，特别是曼陀罗属和假酸浆属物种。全年都存在受感染的杂草意味着它们是病毒二次传播的重要宿主和来源。因此，建议严格控制杂草是降低该地区辣椒病毒感染发生率的重要措施。
