Lawn diseases are different to Lawn Pests. Though there isoften confusion. Basically a lawn disease is either a fungalattack, a virus or even a bacteria.
Most lawn diseases are caused one form or other of fungi. Most can be prevented by a proper maintenance schedule, and in particular proper attention to feeding.
Fungal diseases generally attack weak impoverished lawns - rarely well fed and maintained lawns. The main diseases are outlined below, with links to a more detailed explanations and cures/preventions.
Lawn diseases are not always found early enough, and generally put in an appearance with the wide ranging set of problems under the general heading of brown patches in lawns! In the case of lawn diseases, the brown patch is generally a sign that the fungus or whatever, has got hold and some drastic curative action is necessary.
Far better to try and prevent lawn diseases in the first place. Easier said than done. Follow a good maintenance regime - particularly in relation to mowing correctly and carrying out the operations of top dressing and aeration when required. However, even the most well cared for lawns can fall prey to a fungus disease, and it is often the fact that the lawn is well cared-for that is part of the problem!
There is rather more to caring for your lawn properly, than simply cutting each week and watering when dry!
In general, lawn disease only attack unhealthy or poorly managed grasses. Having to cut grass short for the whim of a sportsman, is not the ideal way to grow a healthy lawn. Professional groundsmen will have their own remedies and ways of keeping diseases at bay.
For the domestic lawn owner, a good health batch of grass plants - around 500 or so in a square foot of lawn - is the best way forward, for most diseases of plants - and animals - can be largely prevented with a healthy being!