In vitro screening of turfgrass species and cultivars for resistance to dollar spot

Authors: ESPEVIG, TATSIANA - Norwegian Institute Of Bioeconomy Research(NIBIO); SUNDSDAL, KRISTINE - Norwegian Institute Of Bioeconomy Research(NIBIO); AAMLID, TRYGVE - Norwegian Institute Of Bioeconomy Research(NIBIO); Crouch, Jo Anne; BRURBERG, MAY - Norwegian Institute Of Bioeconomy Research(NIBIO); TORP, TORFINN - Norwegian Institute Of Bioeconomy Research(NIBIO); NORMANN, KARIN - Asbjørn Nyholt; USOLTSEVA, MARINA - Botaniska Analysgruppen; ENTWISTLE, KATE - National Turfgrass Federation

Submitted to: International Turfgrass Society Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2021
Publication Date: 5/28/2021
Citation: Espevig, T., Sundsdal, K., Aamlid, T.S., Crouch, J.A., Brurberg, M.B., Torp, T., Normann, K., Usoltseva, M., Entwistle, K. 2021. In vitro screening of turfgrass species and cultivars for resistance to dollar spot. International Turfgrass Society Research Journal. https://doi.org/10.1002/its2.78.
DOI: https://doi.org/10.1002/its2.78

Interpretive Summary: Dollar spot diseases affecting turfgrass on golf courses and lawns cause millions of dollars of damage globally each year. Until recently, dollar spot was not known in Scandinavian countries, possibly due to the region's unique climate. Since the turfgrass industry in Scandinavian countries rarely uses chemical pesticides, dollar spot is proving very difficult to control in the region, and information is needed to help manage the disease. In this research we tested the aggressiveness of ten different samples of the dollar spot fungi from Scandinavia, the United Kingdom and the United States on nine different types of turf grasses commonly grown in Scandinavian countries. Pathogens of U.S. origin were more aggressive than pathogens originating in Sweden and Denmark. Overall, aggressiveness did not correspond to pathogen species, and samples of the same species varied in aggressiveness. This research will be used by turfgrass pathologists, agronomists, extension agents, and golf course managers working to define the risks and mitigate the effects of dollar spot disease in Scandinavia.

Technical Abstract: Dollar spot, caused by at least five Clarireedia species (formerly Sclerotina homoeocarpa F. T. Benn), is one of the most economically important diseases worldwide including Scandinavia. There is no available information from Scandinavian variety trials on resistance to dollar spot in turfgrass species and cultivars (http://www.scanturf.org/). Our in vitro screening of nine turfgrass species comprising a total of 20 cultivars showed that on average for ten Clarireedia isolates of different origin, the ranking for dollar spot resistance in turfgrasses which are commonly used on Scandinavian golf courses was as follows: perennial ryegrass=slender creeping red fescue > strong creeping red fescue > Kentucky bluegrass = velvet bentgrass > colonial bentgrass = Chewings fescue = creeping bentgrass = annual bluegrass. Significant differences in aggressiveness among Clarireedia isolates of different origin were found in all turfgrass species except annual bluegrass (Poa annua L.). U.S. C. jacksonii isolates MB-01 and SH44 were more aggressive than those from Denmark and Sweden (14.10.DK, 14.15.SE and 14.16.SE) in velvet bentgrass and creeping bentgrass; and the Swedish isolate 14.112.SE was generally more aggressive than 14.12.NO despite the fact that they were most likely of the same Clarireedia spp. The U.S. C. monthethiana isolate RB-19 had similar aggressiveness as the Scandinavian C. jacksonii isolates but was less aggressive than two other U.S. isolates (MB-01 and SH44). Thus, it appears, that aggressiveness of Clarireedia isolates is not species-specific but depends on geographic origin or/and varies significantly within certain Clarireedia species.