Brown patch and fungal disease in your lawn: how to identify and stop it

Circular brown patches that appeared almost overnight and are spreading by the day. A water-soaked, greasy look to the leaf early in the morning. Sometimes a faint pink or orange tinge at the edges, or a thin cottony web visible in the first light before the dew burns off. If that is what you are looking at, this is not grubs and it is not dry soil. It is fungal disease, and the harder you try to fix it with water and fertiliser, the faster it tends to spread.

Why feeding and watering makes it worse

The instinct when a lawn starts browning off is to water it more and feed it. With fungal disease, both can make it worse. Fungal pathogens thrive in moisture, so extra watering, especially in the evening when the leaf stays wet overnight, gives the disease exactly the conditions it wants. And a flush of nitrogen produces soft, lush new growth that is more susceptible to infection, not less. You end up feeding the disease rather than the lawn.

Fungal disease needs a fungicide. Not more water, not more fertiliser. Once you recognise what you are dealing with, it is very treatable. The key is identifying it correctly and acting before it spreads through the whole lawn.

The common lawn diseases in Australia

Several fungal diseases affect Australian lawns, and they tend to appear when warmth and moisture combine, through spring, summer and into autumn, particularly in humid weather or where the lawn stays wet overnight.

Brown patch shows as roughly circular brown patches that can expand quickly, sometimes with a darker smoke-grey ring at the advancing edge in the early morning. It favours warm, humid conditions and lawns that stay wet.

Dollar spot appears as small, silver-dollar-sized straw-coloured spots that can merge into larger patches. Look for an hourglass-shaped lesion on individual leaf blades. It often shows up in lawns low on nitrogen.

Anthracnose, grey leaf spot, fusarium, take-all patch and helminthosporium are the other diseases that affect Australian turf. They differ in appearance and in which conditions bring them on, but they share the same underlying story: a fungal pathogen taking hold in turf that is stressed, wet, or both.

If you are not certain what you are looking at, send us a photo at info@turfandsurf.com.au, ideally taken early in the morning while the signs are clearest, and we will help you identify it.

The product that stops it

Impala is a dual-active systemic fungicide, and it controls all of the diseases above: dollar spot, brown patch, anthracnose, grey leaf spot, fusarium, take-all patch and helminthosporium. It contains 96g/L azoxystrobin and 194g/L triticonazole, two actives from different mode-of-action groups. That combination means broader disease control and a lower risk of the fungus developing resistance than you get from a single-active product.

Being systemic, it is absorbed through the leaf, crown and root within 24 to 48 hours, so it is protected from being washed off soon after it dries and it works from inside the plant. It acts both preventatively and curatively, which means it works as a planned defence when conditions favour disease and as an urgent response when disease is already visible. A single application gives up to 28 days of protection.

How to apply it

The rate is 60ml per 100m2 in 350ml to 1L of water per 100m2, through a backpack or garden sprayer. One 250ml bottle covers roughly 416m2 per application.

A few points from the label that matter:

• The best results come from applying before symptoms appear, when the weather is turning warm and humid and disease is likely. Prevention is far more effective than trying to cure an established outbreak.
• Apply no more than 2 consecutive Impala applications at 28-day intervals, then rotate to a fungicide from a different mode-of-action group. This is essential for stopping the fungus building resistance, and it is part of using the product correctly, not optional.
• Do not apply to stressed or water-deficient turf.
• It is Schedule 5, so wear gloves and eye protection, and keep children and pets off the lawn until it has dried, usually 1 to 2 hours.

One important compatibility rule

Do not apply Vivid on the same day as Impala. Vivid contains ferrous sulphate, which is incompatible with Impala both in the tank and on the leaf. If your lawn is on the Turf and Surf program and you are treating disease, simply apply the two on separate days. Every other liquid product in the program is compatible. Also avoid mixing Impala with any other high-salt product or fertiliser.

What to expect after you spray

Within 24 to 48 hours the actives are absorbed and fungal activity slows. Over the following 3 to 7 days the disease stops spreading into healthy turf. One thing to be clear about: leaf that is already damaged will not turn green again. The disease has killed that tissue. What happens instead is that the spread halts, and over the next 1 to 4 weeks clean new growth comes through to replace the damage. So do not judge it by whether the brown goes green. Judge it by whether the patch stops growing, which it will.

Complete the program

Impala controls the disease in front of you. The longer-term answer is a lawn that does not get sick as easily in the first place. Fungal disease takes hold most readily in turf that is stressed, poorly drained, shallow-rooted or watered at the wrong time of day. A lawn with strong roots, healthy soil biology and good water penetration is far more resistant.

That resilience is what the Starter Pack and the full 5-step program build from the ground up. Correct watering habits help too: water deeply and in the morning, so the leaf dries through the day rather than staying wet overnight.

Frequently asked questions

How do I know if it is fungal disease and not grubs or dry patches?
Fungal disease usually shows as circular or spreading patches, often with a water-soaked or greasy look to the leaf in the early morning, and sometimes coloured edges or a faint web. Grub damage lifts away like loose carpet with the roots eaten off underneath. Dry patches bead water on the surface rather than absorbing it. If you are unsure, send us an early-morning photo at info@turfandsurf.com.au.

Can I use Impala before I see any disease?
Yes, and it is the more effective way to use it. Applied preventatively when the weather is warm and humid and disease is likely, Impala stops outbreaks before they start. Once disease is established it is harder to control and needs precise timing.

Will my brown patches turn green again after I spray?
The already-damaged leaf will not recover, because that tissue is dead. What Impala does is stop the disease spreading, and clean new growth then fills in over the following weeks. Judge success by the patch no longer growing, not by the existing brown greening up.

Can I apply Impala with my Turf and Surf products?
Yes, with one exception. Do not apply Vivid on the same day as Impala, because Vivid contains ferrous sulphate which is incompatible. Apply them on separate days. Every other product in the program is compatible.

Why can I only apply it twice in a row?
Using the same fungicide group repeatedly lets the fungus build resistance to it. Applying no more than 2 consecutive Impala applications and then rotating to a different mode-of-action group keeps the disease from adapting, and keeps your control working long term.

Is Impala safe on buffalo?
Yes. Impala is registered for all common Australian turf varieties, including buffalo, couch, kikuyu and zoysia.