Lawn Disease - Leaf Spot

Author: Stefan Palm   Date Posted: 1 September 2017 

Leaf spot (historically referred to as Helminthosporium but now known as Bipolaris, Drechslera, and Exserohilum spp.) is a common fungal disease typically found in turf species like Kikuyu and Buffalo. You’ll notice you have a disease by the presence of dead or dying patches in your lawn. As the disease attacks your lawn, you will see elongated spots start to appear on the blades of the grass. These spots are usually brown, tan or olive in colour and will start small then quickly enlarge to half a cm in length. Left untreated, leaf spot will begin to cause noticeable brown patches in your lawn which can spread across the whole lawn if left untreated. Your lawn may thin out which can result in bare patches.

Leaf spot is worst during the summer months where temperatures are between 26-35 degrees. Ideal conditions for the fungus exist during humid weather where moisture heats up in the thatch of the grass. Warm, still nights complete the picture so when spores land on the lawn, they begin to multiply in this favourable environment.   Other factors which increase the likelihood of leaf spot outbreak include lawns which are subject to drought stress and lawns that are over fertilised during summer.

There are some things that you can do to give your lawn some natural resistance to diseases like leaf spot which include making sure your lawn is maintained in a healthy state (watered, mown and fertilised properly) and making sure that you avoid watering in the evening, prior to midnight. Watering in the evening during summer can result in the lawn staying damp all night whhen you will need to apply a fungicide. Fungicides that contain Mancozeb or Daconil are ideal and should be applied at the first signs of ich of course results in an ideal environment for funguses to grow. If you are maintaining a healthy lawn and still manage to get an outbreak, toutbreak. Remember, a strong, healthy lawn is always the best defence against dealing with disease and when combined with a fungicide, you can expect the best results.

If you need any help identifying or treating a lawn problem, please give Paul Munns Instant Lawn a call on 8298 0555 or send us an email at

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