细叶结缕草褐斑病病原菌的分离、鉴定及杀菌剂室内毒力测定

Isolate and identify the pathogen of brown patch on Zoysia tenuifolia and toxicity test of fungicides against the pathogen

于2014~2016年,对海南省和广东省由细叶结缕草(Zoy siatenuifolia)建植的多个草坪绿地进行病害调查,发现一种引起块状分布的枯死病害对该草的观赏和使用价值产生严重危害。对各地病害样品取样,并采用植物病理常规组织分离法对病原菌进行分离,根据病原菌培养性状、形态学特征、致病性测定和分子生物学特征(r DNA-ITS序列)鉴定出引起细叶结缕草褐斑病的病原菌为立枯丝核菌(Rhizoctonia solani)。室内测定9种杀菌剂对病原菌毒力的试验,结果表明:5%烯唑醇对R.solani毒力最强,其EC50值为0.055 mg/L;毒力最低的为70%甲基托布津,其EC50值为7.021 mg/L。

Field surveys were carried out from 2014 to 2016 in several green lawns of Hainan and Guangdong Province of China. A damage disease which seems like brown patch could affect Zoysia tenuifolia was observed and it has serious influence on the ornament and use value of the grass. The normal tissue isolation method of plant pathology was used to isolate the pathogen. Based on comprehensive analyses cultural observations,morphological characteristics,pathogenicity test and its internal transcribed spacer（ ITS） r DNA region nucleotide sequence,the pathogen causing brown patch was identified as Rhizoctonia solani. The toxicity of 9 fungicides to the pathogen was tested in laboratory,the results show that5% diniconazole had the highest inhibitory effects on Rhizoctonia solani with EC50 at 0. 055 mg/L,whereas 70% thiophanate-methyl had lowest inhibitory effects on R. solani with 7. 021 mg/L. The results provide the method for identify the pathogens and may help exploring management strategies.