Since the heavy rain in October when our lawn got partially waterlogged, we’ve got this horrible crusty fungus eating the couch grass.

Anyone know what it is and how to get rid of it?

 

 

Looks similar to Fusarium nivale,  snow mould. I don't believe that fungi actually eat grass. If the grass isn't growing well, this is just part of a problem you are having with the soil / available nutrients, do you fertilise?

The traditional treatment would be a copper based fungicide, OR: just let it disappear. If it reappears next year you may want to take measures to alter the pH of your soil (easy, don't worry), OR: do nothing.

Interesting, I agree that it’s not ‘eating’ the grass but it is covering the soil and preventing any new growth.

I don’t fertilise at the moment but this sounds like the best solution - along with breaking up the fungus with a rake.

Can you recommend a good couch fertiliser available in LoS?

17 hours ago, 3STTW said:

Interesting, I agree that it’s not ‘eating’ the grass but it is covering the soil and preventing any new growth.

I don’t fertilise at the moment but this sounds like the best solution - along with breaking up the fungus with a rake.

Can you recommend a good couch fertiliser available in LoS?

OK, scrape it up if you want to, but it won't improve growth. If you can't find a specific lawn fertiliser in Thaiwatsadu then you can try a rice fertiliser, but go easy on the dose, not more than 10% nitrogen /M2 and see how it goes aas you water regularly...

I had a go and raked about 5sqm with pretty good results. It rips up the fungus and the sickly grass (like hay) and leaves the healthy green shoots behind. I haven’t watered it for a week so the fungus is dry and crispy which makes the job that much easier.

 

I also noticed that where the worst patches are the topsoil has all but washed away so I’ll rake in some potting mixture tomorrow.

 

The couch grass is pretty good at re-covering bare patches. Hopefully the potting compound and some worm castings will help it along.

12 hours ago, 3STTW said:

I also noticed that where the worst patches are the topsoil has all but washed away

If you have soil erosion, simply replacing won't help.  You will need to either re-grade or put in rocks or whatever to stop the erosion.