This condition is as the name suggests quite simply the result of the lawn being allowed to dry out during hot weather. It can be more problematic when your soil is dry and sandy rather than dense and heavy as these soils are much more susceptible to drying out. Eventually this disease becomes more difficult to treat than by simply watering the lawn as the soil particles take on a ‘water repellent’ quality that can only be remedied by the rainfall in the autumn and winter months.
To prevent dry patch disease from striking is simply a case of maintaining a regular watering schedule in the summer months (and sticking to it!). It can also be useful to use a wetting agent to help the lawn retain its hydration, and better still to aerate the lawn before doing so, this will ‘open up’ the lawn and allow the wetting agent and water to penetrate right into the soil. Besides this, you should employ all the usual techniques of scarification and aeration to remove thatch and to allow the grass to breath and take on water more easily.