The causal agent for Melting Out and Leafspot is a group of fungii that includes Drechslera spp & Curvularia spp. It can affect all grass species but turf when close mown is more susceptible particularly in high nitrogen fertiliser regimes. The causal fungi usually first invade the leaves, producing small brown spots. As the disease worsens, the spots on leaf blades expand and produce a dark purplish-red oval border around a tan center. The spots enlarge until the entire width of the leaf blade is blighted. The leaf-spotting or leaf-blighting phase is less damaging to the turfgrass than is the melting–out (crown and root-rot) phase of the diseases. In melting–out, the crowns and roots are damaged, causing severe thinning of the turf. The problem is exacerbated by the addition of nitrogen fertilisers.
- Avoid high applications of nitrogen. Fungicides to be effective must be employed during the leaf spot phase. Once the disease has moved into the melting out phase applications of fungicide will have limited effect. Contact the office for advice on the appropriate fungicide.