Should I water that in?

This is easily the most frequent question I get from golf course superintendents during the growing season. It is a difficult question, and there isn't always an easy answer.

We know that watering fungicides into the root zone is important for effective control of root diseases. However, in the real world, golf course superintendents apply fungicides to control a combination of root and foliar diseases, but we don't always know what effect watering-in has on foliar disease control.

To answer this watering-in question, you need to identify the primary disease you're trying to control, know where this pathogen attacks the turf plant, and understand how the selected fungicide moves in the plant after application.

In most cases, if a root disease is the primary target for a fungicide application, then it should be watered-in immediately after application. Once the spray dries on the leaves, it will be locked into the foliage and will not get into the root zone. Exceptions to this rule are the true systemic fungicides, like fosetyl-Al and the phosphite salts. These products are translocated downward in the plant and do not need to be watered-in.

The Fungicide Selection Tool, a new feature on our TurfFiles website, can help you select the best application technique for your fungicide applications. After selecting your turf species and the diseases you are trying to control, a list of fungicides is displayed. The list is ordered based on average efficacy against the selected diseases. After selecting a product or products to apply, you are taken to a page that displays mode of action, efficacy rankings, risks for fungicide resistance, rates and application intervals, and application instructions for each selected disease.