Cultural management of weeds in turfgrass: A review

Cultural management of weeds in turfgrass is the use of mowing, fertilization, irrigation, cultivation, planting, and turfgrass selection to affect weed populations. There is consensus in the literature on a few cultural factors influencing some weeds in cool-season turfgrasses. Taller mowing height, 4 to 8 cm, depending on turfgrass, reduces populations of crabgrasses (Digitaria spp.) in Kentucky bluegrass (Poa pratensis L.) and fescues (Festuca spp.). A high rate of N fertilization (100-300 kg N ha(-1) yr(-1)) reduces populations of crabgrasses, dandelion (Taraxacum officinale G.H. Weber ex Wiggers), and other broadleaf weeds in cool-season turfgrasses. Annual bluegrass (Poa annua L.) may be favored by this high rate of fertilization. Fertilization of turfgrasses when they are not actively growing increases weeds. Slow-growing grasses such as zoysiagrasses (Zoysia spp.) have more weeds at high N fertilization rate. Environmental stresses including drought injury, unnecessary aeration or vertical mowing, biotic stress such as nematode and insect herbivory, and diseases contribute to weed colonization. Adapted cultivars and species of turfgrasses that are genetically resistant to biotic and environmental stresses have the fewest weed problems. Adapted turfgrasses can sometimes be effectively managed in the absence of herbicides, especially if they are well established. The generalized mechanisms for cultural management of weeds are poorly understood. Research is needed on optimizing the choices of herbicide and/or cultural practices as part of an integrated management system for turfgrass.