Biology and pathogenicity factors of Rutstroemia floccosum and the effects of lightweight rolling on dollar spot disease incidence in creeping bentgrass putting greens.

摘要

A study to investigate the effects of light-weight rolling on the reduction of dollar spot was conducted between 2008 and 2009. Treatments rolled in the afternoon exhibited similar disease reduction as treatments rolled in the morning when compared to the control. A twice day-1 rolling treatment exhibited significantly less disease than all other treatments and resulted in greater rootzone soil volumetric water content (VWC) in both 2008 and 2009, when compared to the non-rolled control. Rolled treatments exhibited increases in fatty acid abundances associated with common bacteria when rootzone soil phospholipid fatty acids (PLFA) were analyzed. Furthermore, a general trend towards higher total bacterial PLFA abundances was present in rolled treatments. These results suggest that daily, season-long, light-weight rolling on putting greens may contribute to dollar spot reductions through the alteration of microbial populations in the upper rootzone. Additionally, afternoon rolling treatments suggest mechanisms other than dew and guttation removal to be responsible for disease reductions. R. floccosum isolates were examined for oxalic acid (OA) and cell wall degrading enzymes (CWDE) production. Non-virulent isolate Sh12B displayed high levels of CWDEs and OA production to a lesser extent when compare to virulent isolates. This suggests that OA and CWDEs may not be sole pathogenicity factors necessary for R. floccosum infection on turfgrass.