Global Distributions of Clarireedia Species and Their In Vitro Sensitivity Profiles to Fungicides

Jian Hu,Shan Jiang,Kurt Lamour,Yinglu Dong,Yu Chen,Huangwei Zhang,Zhimin Yang,Jun Liu

doi:10.3390/agronomy11102036

Jian Hu, Shan Jiang + Show 6 more

Open Access

https://doi.org/10.3390/agronomy11102036

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Abstract

Dollar spot is reported to be caused by multiple Clarireedia species and is a serious problem on many turfgrasses around the world. To our knowledge, the distribution of different Clarireedia species and their sensitivity profiles to fungicides remains unknown. In this study, a total of 275 isolates were characterized by ITS sequence. Amounts of 124, 59 and 75 isolates were identified as C. jacksonii, C. monteithiana and C. paspali, respectively, while each species of C. homoeocarpa and C. bennettii had only five isolates. Four and three isolates were identified as two potential new species, which remained to be further characterized. C. jacksonii and C. monteithiana were distributed worldwide, while C. paspali was restricted to China. Of the isolates with host information, 81% (93/115) and 19% (22/115) of C. jacksonii isolates were collected from C3 and C4 plants, respectively, 97% (56/58) of the C. monteithiana isolates were collected from C4 plants and all C. paspali isolates were collected from C4 plants. The coexistence of different Clarireedia species on the same C4 host type in the same locales was found in Shanghai (Paspalum vaginatum), Jiangsu (Paspalum vaginatum) and Florida (Cynodon dactylon). The study revealed that differential fungicide sensitivity patterns were observed in different species in Clarireedia for the first time. Similar differential sensitivity profiles were also found in the locales with coexistence of at least two species. The findings from this study suggest that the adjacent coexistence of different Clarireedia species and the differential fungicide sensitivity profiles of different species will complicate dollar spot disease control.

Highlights

Dollar spot, caused by the Clarireedia species, is one of the most economically important diseases of turfgrass worldwide [1,2]
This study reported on the distribution of Clarireedia species around the world, and the differential sensitivity patterns of C. jacksonii, C. monteithiana, and C. paspali populations to TM, propiconazole and boscalid, but not to iprodione
All isolates in Europe and the northern regions of the USA and China were C. jacksonii, which indicates a strong geographic distribution (Figure 1). We propose that both host type and geography are likely to influence the distribution of Clarireedia species

Summary

Introduction

Dollar spot, caused by the Clarireedia species (formerly Sclerotinia homoeocarpa), is one of the most economically important diseases of turfgrass worldwide [1,2]. The five species in Clarireeida include the type species for the genus, C. homoeocarpa and four recently characterized species, C. bennettii, C. jacksonii, C. monteithiana and C. paspali. Among the five species of Clarireedia that have been identified, C. homoeocarpa has only been found in the United Kingdom, whereas C. bennettii is primarily found in the United. The two species appear to be historical and represent a minority of the isolates which cause dollar spot. The modern species with worldwide distribution are C. jacksonii and C. monteithiana, which are widely distributed in

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