Lawn diseases

The main cause of lawn diseases is fungus. You will recognise fungus from the emergence of spots, circles, patches or the presence of different colours like brown, yellow and red on your lawn.

 

These are some common lawn diseases:

 

By Roelof Strydom

Brown patch

Brown patch does not affect the root system of lawns, but causes rings or patches of blighted grass that can measure from 12cm to 3m in diameter. It favours high humidity areas and can also occur on grass that is wet for extended periods.

 

Treatment: Spray with a fungicide containing chlorothalonil and/or propiconazole.

 

Dollar spot

Dollar spot thrives in humid climates and causes brown to straw-coloured sunken patches in the lawn. It infects areas with low nitrogen levels and becomes worse in dry soils. To prevent dollar spot, aerate your lawn frequently and water it in the morning. Also fertilise your lawn regularly to improve its nitrogen levels.

 

Treatment: Spray with a fungicide containing chlorothalonil.

 

Rust

Rust initially causes light yellow flecks to appear on the blades of grass. These flecks enlarge, elongate and turn yellow in colour. The entire grass blade turns yellow from the tip to the base. This disease occurs in moist, low light areas and is common in lawns that grow very slowly. A good way of getting rid of rust is to aerate your lawn, as well as water it in the mornings and reduce shade on the grass. Regular fertilisation to increase the nitrogen levels will also help.

 

Treatment: Spray with a fungicide containing chlorothalonil or mancozeb.

 

You should also look out for mushrooms on the lawn, as mushrooms are in most cases a sign of disease. Because lawn diseases can do serious damage to a lawn in a short amount of time, they should be treated immediately. 
 

Read about different lawn types lawn pests and lawn weeds common to South Africa.