Lawn Disease Control: How to Identify and Treat Common Turf Diseases
Australian lawns · last reviewed
A patch of dead or discoloured turf gets blamed on drought, dog urine or a mowing scalp long before anyone considers a fungal disease, because most turf diseases look like ordinary stress at a glance. Four fungi cause almost everything The Lawn IQ gets asked about — Brown Patch, Dollar Spot, Anthracnose and Winter Fusarium — and while one broad-spectrum fungicide covers all four, they favour different weather and show up as different shapes and colours. Knowing which one you have is worth a few minutes before you spray anything.
How to tell which lawn disease you have
Fungal disease almost always shows up as a patch rather than a single dead blade, and the shape, colour and the weather it appeared in are the best clues you have before you spend anything.
Confirm it's fungal before you treat it
Check the leaf first — a fungus usually shows as a spot or lesion on the leaf blade, often starting near the spine. If it looks deeper than that, pull out a runner and look at the internodes, where the leaves come out: a dark spot or a rotten-looking join between them is another sign you are dealing with disease rather than drought or wear.
What you see, and what it usually means
| What you see | Likely cause | What to do |
|---|---|---|
| Small, straw-coloured spots about the size of a coin, merging into larger patches of thin or dead turf | Dollar Spot Sclerotinia homeocarpa | Read the full guide and treat with Tombstone Duo below |
| Circular brown or tan patches that expand quickly in warm, humid weather, sometimes with a darker ring at the leading edge in the early morning | Brown Patch Rhizoctonia solani | Treat with Tombstone Duo below |
| Irregular yellow-to-brown blotches on turf that is already under stress — heat, compaction or a low mowing height — and easy to mistake for drought | Anthracnose Colletotrichum spp. | Treat with Tombstone Duo below |
| Circular reddish-brown to orange patches appearing in cool, wet weather — autumn and winter, often right after frost or a long run of overcast days | Winter Fusarium Fusarium roseum | Treat with Tombstone Duo below |
| Turf that feels spongy underfoot and lifts like carpet, or runners chewed back to the stolon | Not a disease — that's lawn grubs | Read the lawn grub guide instead |
When lawn disease takes hold in Australia
Brown Patch, Dollar Spot and Anthracnose are warm-season disease pressure — they take hold in humid, still conditions with extended leaf wetness, which across most of Australia means late spring through autumn, especially after rain or heavy dew that never properly dries off the leaf. Winter Fusarium runs the opposite calendar: cool, wet conditions through autumn and winter, often showing up right after a frost or a long stretch of overcast days.
- Extended leaf wetness raises the risk for all four, whatever the season. Dense shade, poor airflow and watering late in the day all keep the canopy wet for longer than it needs to be.
- Underfed or unevenly fed turf is more vulnerable across the board. A lawn that is not actively growing cannot outgrow a minor infection the way healthy turf can.
How to treat lawn disease
Tombstone Duo combines two active ingredients — tebuconazole and trifloxystrobin — that work at different stages of the fungus's lifecycle, giving both preventative and curative control of Brown Patch, Dollar Spot, Anthracnose, Winter Fusarium and several other turf pathogens.
The current label rate, timing and re-entry instructions are on the product page — read the label before you apply anything, and treat it as the authority over anything written here.
Tombstone Duo is a liquid, applied with a calibrated sprayer — calibrate your sprayer first, so you are applying the label rate rather than guessing at it. If it is more than disease you are dealing with, browse all weed, pest and disease products.
Watch: identifying lawn fungus
Where to look on the leaf, and how to check a runner's internodes if it looks like it might be deeper than the surface — two minutes, out on a Queensland buffalo lawn.
Full video page, with the transcript · Dollar Spot in Lawns: Identifying and Managing This Common Turf Disease goes deeper on one of the four.
Stopping it coming back
The same handful of conditions let every one of these fungi in, whichever one you are treating: a lawn that is underfed or unevenly fed cannot outgrow a minor infection, leaf that stays wet overnight from evening watering or heavy shade gives disease longer to establish, and thatch, compaction and blunt mower blades all trap moisture at the surface. None of that is disease-specific — it is the same list whether the outbreak is Dollar Spot or Brown Patch. Dollar Spot in Lawns walks through the fix for each factor in more detail.
Lawn planLawn Recovery PlanBefore you give up, give your lawn a second chance.Common questions
What does lawn disease actually look like?
A patch of turf that is a different colour or thickness than the lawn around it — bleached, brown, tan, reddish or yellowing — usually with the fungus still active right at the edge of the patch rather than in the dead centre.
Is it caused by too much water, or not enough?
Usually too much surface moisture rather than drought — leaf that stays wet overnight from evening watering, heavy dew or poor airflow is what most of these fungi need to establish. Drought stress can make turf more vulnerable generally, but it is not the direct cause.
Will it go away on its own?
Sometimes the damage is mostly cosmetic and eases once the weather that favoured it passes, but a repeat outbreak weakens the turf and opens the door to weeds and other problems — it is worth treating and fixing the underlying conditions rather than waiting it out.
What's the difference between Brown Patch and Dollar Spot?
Mostly size and weather. Dollar Spot shows as small, coin-sized spots that merge together, and favours mild days with cool, damp nights. Brown Patch shows as larger circular patches and spreads fast in hot, humid weather. Both respond to the same fungicide.
Is Tombstone Duo safe around kids and pets?
Follow the drying time, re-entry and any other precautions on the label you are holding — it is the authority on when it is safe to let people, kids or pets back onto the treated area.