Biology, Ecology, and Herbicidal Control of Perennial Sedge Species Found in Managed Turfgrass Systems.

Abstract

Perennial sedge species (Cyperaceae) are increasing in their prevalence in managed turfgrass systems. Research evaluated herbicidal control and physiological activity of herbicides on perennial sedges; ecological factors influencing the spatial distribution of perennial sedge species, and phenological characteristics of perennial sedges. Experiments largely focused on green and false-green kyllinga (Kyllinga brevifolia and K. gracillima) with one experiment focused on yellow and purple nutsedge (Cyperus esculentus and C. rotundus). Soil + foliar applied CGA-362622 and halosulfuron controlled green and false-green kyllinga greater than foliar-applied. In addition, soil + foliar and soil-applied CGA-362622 controlled yellow and purple nutsedge greater than foliar-applied, indicating that both foliar and root absorption are important to increasing control of perennial sedges. In field experiments, CGA-362622 applied singly controlled green and false-green kyllinga greater than halosulfuron applied singly; however, no difference was observed between sequential applications of these two herbicides. The combination treatment of imazaquin + MSMA controlled green and false-green kyllinga greater than or equal to all herbicide treatments including CGA-362622 applied sequentially. Based on studies evaluating the physiological activity of CGA-362622 and halosulfuron in green and false-green kyllinga, the observed control difference between single applications of these herbicides could not be attributed to absorption, translocation, or metabolism. In evaluating the spatial distribution of green and false-green kyllinga in managed turfgrass, it was observed that both species are correlated with areas of increased soil moisture. Green kyllinga correlated with increasing soil sodium across three sites, indicating a potential halophytic response. While both species correlate with numerous edaphic variables, observations were not consistent across sites. Further evaluation of the interrelationship of elevation and edaphic variables indicates that heterogeneity within the soil environment is correlated with subtle changes in elevation. Experiments evaluating the phenological characteristics of green and false-green kyllinga indicate that green kyllinga's shoot, root, and rhizome growth rate is faster than that of false-green kyllinga; however, green kyllinga does not survive the winter in the piedmont region of North Carolina.