Many species of fungi and other diseases attack lawns that aren't in good condition. Lawn diseases usually announce their presence with patches of dead grass. The way the patches spread and the shape and color they take on can indicate (to a trained eye) the type of problem that's lurking beneath the surface. See Lawn Care For Dummies for details on identifying diseases.
Lawn diseases are nearly impossible to control with chemicals, but good lawn care usually keeps the diseases at bay. The best strategy is to avoid overfertilizing, which produces susceptible growth. No organic fungicides are available, but seaweed has been effective in some cases.
If diseases are persistent, renovate the lawn and seed with a mixture of disease-resistant grass varieties. See the earlier section "Aerating and Renovating Your Lawn" for further details.
Was this article helpful?