Iron chlorosis is aggravated by high levels of phosphorus in the soil. Where iron chlorosis is a problem, phosphorus fertilization should be kept to a minimum. Weed, Pest and Disease Management . The annual grasses can be effectively controlled with timely applications of preemerge herbicides. The broadleaved weeds are effectively controlled with hormone type herbicides.
Insects including white grubs, billbugs and sod webworms can destroy plantings of bluegrass.
Insect populations should be monitored so that timely insecticide applications can be made. Pest management in this manner is much more cost effective than either routine insecticide applications or replanting large areas of bluegrass turf. Major diseases of bluegrass turf in the transition zone include Fusarium, Helminthosporium leaf spot diseases, rust and powdery mildew. Selecting blends of Kentucky bluegrass with different degrees of resistance to these diseases is one means of control. Overseeding bluegrass turf with perennial ryegrass or planting mixtures of bluegrass and ryegrass provides a good suppresion of Fusarium blight, a disease which causes a bleaching of leaves and severe rotting of roots.