Large patch is a destructive disease occurring in both the fall and spring when extended periods of saturated soil and overall wetness create ideal conditions for development. The best way to keep large patch off your course is to treat for it preventively.


Preventative treatment for large patch is simple: two fall applications and one spring application. The initial fall application occurs from mid-September to early October, with the remaining fall application then applied one month later. In the spring, the last application is applied from the mid-March to late April timeframe. Timing will be weather specific for the location.

ArmorTech TEB 360 XL and ArmorTech Zoxy-T are two excellent products that combat large patch.

  • ArmorTech TEB 360 XL is applied at a rate of .6oz/1000, twice in the fall and once in the spring.
  • ArmorTech Zoxy-T is applied at a rate of .75oz/1000, twice in the fall and once in the spring.

While not as recommended, if you miss any of the fall applications, you could still treat for large patch in the spring. You will need to use higher rates of ArmorTech TEB 360 XL and Zoxy-T, however. The higher rates will result in the same amount of product being put down as applying two applications (TEB 360 XL at 1.6oz/1000 and Zoxy-T at 1.5 oz/1000).

Budget Concerns

If three large patch applications do not fit in your budget, apply a fall and spring application of TEB XL 360 and Zoxy-T. If treating the entire infected area is not in your budget, be strategic in how you apply the three large patch applications. Treat the areas that have been historically worse with the most significant amount of the three applications and apply less product in the areas that have not been affected as bad. Also, controlling moisture levels heading into fall and keeping the moisture level lower has shown to reduce large patch severity in the spring.