Overwintering of Sclerotium rolfsii and S. rolfsii var. delphinii in Different Latitudes of the United States

Abstract

Previously known only from the southern United States, hosta petiole rot recently appeared in the northern United States. Sclerotium rolfsii var. delphinii is believed to be the predominant petiole rot pathogen in the northern United States, whereas S. rolfsii is most prevalent in the southern United States. In order to test the hypothesis that different tolerance to climate extremes affects the geographic distribution of these fungi, the survival of S. rolfsii and S. rolfsii var. delphinii in the northern and southeastern United States was investigated. At each of four locations, nylon screen bags containing sclerotia were placed on the surface of bare soil and at 20-cm depth. Sclerotia were recovered six times from November 2005 to July 2006 in North Dakota and Iowa, and from December 2005 to August 2006 in North Carolina and Georgia. Survival was estimated by quantifying percentage of sclerotium survival on carrot agar. Sclerotia of S. rolfsii var. delphinii survived until at least late July in all four states. In contrast, no S. rolfsii sclerotia survived until June in North Dakota or Iowa, whereas 18.5% survived until August in North Carolina and 10.3% survived in Georgia. The results suggest that inability to tolerate low temperature extremes limits the northern range of S. rolfsii.

Development of a Rapid Method Using Oxalic Acid to Assess Resistance Among Hosta Cultivars to Petiole Rot Caused by Sclerotium rolfsii var. delphinii

“…Within each replication, there were three plants per cultivar; petiole bases of two plants of each cultivar were inoculated with carrot disks infested with S. rolfsii var. delphinii on 4 July and 11 July in 2005 and 2006, respectively (18). Moistened sterile cotton balls covered the carrot disks to prevent inoculum from drying out.…”

“…Available information suggests that S. rolfsii var. delphinii is the predominant petiole rot pathogen in the northern United States, whereas S. rolfsii is predominant in southern states (2,18). Using resistant cultivars can be an effective method of managing diseases incited by these fungi (11).…”

Sclerotinia homoeocarpa Overwinters in Turfgrass and Is Present in Commercial Seed

“…A heavy snowfall event in late January of 2013 may have insulated S. homoeocarpa from fluctuating air temperatures, resulting in a greater number of spring isolations in year three. Direct comparisons of these studies to prior research are difficult because most research on fungal pathogen overwintering focuses on survival of spores and often involves artificial manipulations of the pathogen itself or of infected host material [33] , [34] , [35] . However, a few studies have shown that fungal pathogens survive harsh winter conditions in host debris that then serves as primary inoculum in the following spring [36] , [37] , [38] .…”

Antagonistic mechanisms of endophytic Pseudomonas fluorescens against Athelia rolfsii

“…; Yaqub and Shahzad ; Xu et al . ; Jin and Gao ). Atractylodes lancea , which is commonly called Cang Zhu, is an important herbal plant widely used in Chinese medicine for thousands of years.…”