Provide an example of a fungicide class and a disease it commonly targets in turf, and an important label consideration.

• A. DMIs have no restrictions.
• B. Demethylation inhibitors (DMIs) like propiconazole target dollar spot; label considerations include rotation, restrictions on frequency, and protective application times.
• C. DMIs target rust only.
• D. Propiconazole increases weed growth.

Answer: (D)

DMIs, or demethylation inhibitors, are a fungicide class that disrupts fungal cell membranes by blocking sterol synthesis. A typical turf target for these fungicides is dollar spot, a common fungal disease on warm-season and cool-season turf grasses. An important label consideration is to rotate fungicides with different modes of action and to follow any restrictions on how often you can apply the product and when you should apply it (often emphasized as applying preventively or at the first sign of disease). This helps manage resistance and ensures effective control.

The other statements aren’t accurate: DMIs do have label restrictions and are not unrestricted; they don’t target rust exclusively, since they control several diseases including dollar spot and brown patch; and propiconazole does not increase weed growth.