How to treat infected buffalo grass?

[jonniemartin]

I recently did a backyard renovation which included rolling out new Sir Walter Buffalo turf (November 2023). The area sits on a clay base, so we decided to dig down 150mm and backfill with soil, to give the grass a better foundation. The lawn was initially doing really well and growing thickly.

However, recently I think I'm dealing with a pretty significant fungal infection. On reflection, this is likely due to me overwatering the area. At first, areas of the lawn began to thin out, with olive coloured spots appearing on the leaves. These worsened and then started to form brown patches all over the lawn.

After reading some advice on a similar issue, I have aerated the entire lawn and top dressed the brown patches with washed sand, as well as holding off on watering until the lawn is completely dry. I have also applied a round of Sulphate of Potash to the whole lawn (link) to try and speed along the recovery. This was applied about one week ago now.

Since applying the fertiliser, topdressing and aerating - the infection has not gotten significantly worse, but it hasn't really improved either. My main questions:

1. At what point should I look at applying a fungicide, if the mentioned treatment doesn't work?

2. Which fungicide should I apply and is there any risk in applying one when the lawn is so young?

Please see below pictures:

18th November - Clay base Dugout

18th November - Clay base dug out

18th November - Backfilled with Soil

18th November - Turf Layed

23rd December - Lawn Growing Well

8th January - Brown Patches and Fungus Pictures

Today (9th January) - Top-dressed and Aerated.

[jonniemartin]

Thanks @MitchellMc @Noelle - for the advice!

@Noelle - all makes sense, how regularly would you recommend I aerate the area?

@MitchellMc - there’s a lot of rain predicted in Sydney this week, so should be a good test. RE the drainage suggestion, there is a pvc pipe which runs underneath the lawn and connects to stormwater, so could definitely look at adding in and connecting some ag pipe. Do you think that is imperative to do now, or could I wait and see how it goes for a season and if drainage doesn’t improve, look to do this work next spring?

Updated photos (14 Jan). Parts of the lawn doing really well. Brown patches still persist but there are some new runners coming through over the affected areas.

   

 

Thanks again!

[Noelle]

Hi again @jonniemartin 

In your position, I would aerate every three months from early spring through to late autumn. Aerate the whole area but pay special attention to those spots that have browned off as the grass there has probably suffered the most.

I'd also wait to see how all current treatments play out before thinking about laying drainage lines across the lawn area.  Most likely, once the lawn is really well established and its roots have anchored well, additional drainage may not be needed.

[MitchellMc]

Some great advice from @Noelle there, @jonniemartin. Drainage isn't an immediate concern. It's just something to remember if things get worse and the area becomes constantly waterlogged.

Keep us updated.

Mitchell

[jonniemartin]

Thank you all this has been so helpful. Will let you know how it progresses