How long does lawn fungicide last?

First things first. You can see there’s something wrong with your lawn but if you’re not sure what it is, seek advice from your local garden centre.

Or you can refer to our guide to preventing and managing a range of common lawn diseases.

The two main ways of tackling fungal disease are with a contact fungicide or a systemic fungicide.

Contact fungicide

Contact fungicides form a barrier on the outside of leaves and stems, stopping the disease from entering the plant and causing damage. These are best used as a preventative to protect your grass before it becomes infected.

Contact fungicides can be effective for 3-8 days but will stop working when that protective layer is washed off by rain or watering and will need to be reapplied.

Mowing or heavy foot traffic also will reduce effectiveness.

Systemic fungicide

Systemic fungicides penetrate the plant and are translocated to and from the roots, allowing them to work from the inside out. These will attack and kill the fungus on infected plants, whether symptoms are visible or not, allowing for healthy new growth.

Systemic fungicides are most effective when applied early, such as within the first three days, although results depend on the severity of the infection. They’re not washed off by rain and can keep working for longer than a contact fungicide – up to 25 days or more.

Fungicides are available in a range of formulations, including granules, dry powders that must be mixed with water, liquid concentrates, or ready to use sprays.

Liquid fungicides, which require less measuring and mixing, are generally the easiest to use. They also don’t usually need to be watered into the soil.

The best time to apply fungicide will depend on whether you’re using a contact fungicide or a systemic fungicide.

It is usually early in the morning – before bees are foraging – and more than 24 hours before rain is expected.

The spray must be able to dry, but avoid spraying when it’s windy or conditions are otherwise likely to encourage spray drift onto fruit and vegetable gardens.

It might be necessary to spray more than once if conditions favourable to disease persist, but don’t use the same product each time.

Alternate between contact and systemic fungicides as well as using fungicides from different modes of action groups to avoid the development of resistance which can make chemicals less effective.

Always read the product label and follow its instructions for application and safety precautions. Some fungicides registered for turf diseases are not permitted for use in the home garden.

Some fungicides are less toxic than others, but you should always wear gloves, eye protection, boots and avoid skin contact when applying any chemicals to your lawn or garden.

Keep children and pets off your lawn for at least 24 hours after application.

An actively growing healthy lawn is the best defense against pests, weeds and disease.

Some weeds can harbour disease-carrying pests, so keep on top of them as well.

Your lawn care maintenance program should include regular mowing, aeration and thatch removal, application of fertiliser, and deep, infrequent watering. You can read our guide to turf maintenance and lawn care.

There’s also a guide to preventing and managing a range of common lawn diseases.

Indigo Voltar GT 250 5L

Adama Bumper 625EC 1L

Syngenta Posterity Turf 500ml

SureFire Chlortan 720 1L

Indigo Tombstone Duo 500ml

You can browse these and other fungicides in the myhomeTURF online shop.