Cultural practices are the ways in which you establish and manage your landscape to prevent pests or disease from harming your landscape. These practices include properly preparing the soil as well as proper mowing, pruning, fertilization and irrigation. Each is important in maintaining healthy plants. Plants that are old, sick or dying are more susceptible to pests. Insects are only one of many potential causes for unhealthy-looking plants. Diseases, nematodes, drought, nutritional disorders and improper chemical applications can also be damaging.