Moslemi Azin, Ades Peter K, Groom Tim, Crous Pedro W, Nicolas Marc E, Taylor Paul W J
Faculty of Veterinary and Agricultural Science, University of Melbourne, VIC, 3010, Australia.
Department of Forest and Ecosystem Science, University of Melbourne, VIC, 3010, Australia.
Plant Dis. 2016 Dec;100(12):2363-2369. doi: 10.1094/PDIS-05-16-0628-RE. Epub 2016 Sep 30.
Pyrethrum (Tanacetum cinerariifolium) is commercially cultivated for the extraction of natural pyrethrin insecticides from the oil glands inside seed. Yield decline has caused significant yield losses in Tasmania during the last decade. A new pathogen of pyrethrum causing crown rot and reduced growth of the plants in yield decline affected fields of northern Tasmania was isolated from necrotic crown tissue and described as Paraphoma vinacea. Multigene phylogenetic identification of the pathogen also revealed that P. vinacea was a new species different from other Paraphoma type strains. Glasshouse pathogenicity experiments showed that P. vinacea significantly reduced belowground and total biomass of pyrethrum plants 2 months after inoculation. Dull-tan to reddish-brown discoloration of the cortical and subcortical crown tissue was observed in 100% of the infected plants. P. vinacea infected 75% of the plants inoculated with root dip and soil drench inoculation techniques in an inoculation optimization experiment. P. vinacea, the causal agent of Paraphoma crown rot disease, represents an important pathogen that will negatively impact the commercial cultivation of pyrethrum in Tasmania.
除虫菊（白花除虫菊）被商业化种植，用于从种子内部的油腺中提取天然除虫菊酯杀虫剂。在过去十年中，产量下降已导致塔斯马尼亚州出现重大产量损失。从坏死的冠部组织中分离出一种导致塔斯马尼亚州北部产量下降的除虫菊新病原体，该病原体导致冠腐病并使植株生长减缓，被描述为葡萄状拟茎点霉。对该病原体的多基因系统发育鉴定还表明，葡萄状拟茎点霉是一个不同于其他拟茎点霉类型菌株的新物种。温室致病性试验表明，接种2个月后，葡萄状拟茎点霉显著降低了除虫菊植株的地下生物量和总生物量。在100%的受感染植株中观察到皮层和皮层下冠部组织出现暗褐色至红棕色变色。在接种优化试验中，采用浸根和土壤浇灌接种技术接种的植株中，75%受到葡萄状拟茎点霉感染。葡萄状拟茎点霉是拟茎点霉冠腐病的病原体，是一种重要的病原体，将对塔斯马尼亚州除虫菊的商业化种植产生负面影响。
