In recent years there has been an increase in the use of combination fungicides. With the launch of Clean Sweep Trio from Indigo Specialty, we have put some information together on turf combination fungicides. There is a strong case to say that these are the best fungicides for lawns.
The free Guide to Turf Pesticides has more about the specific diseases these control.
Turf combination fungicides include more than a single active ingredient. They have several benefits over straight fungicides, and you can often use these in the home garden for turf disease control.
Their key advantages are:
- An increase in the spectrum of disease control. They control a lot of turf diseases, and are excellent for brown patch.
- They often contain new actives to the Australian turf market. This is the case with Lexicon Intrinsic and Clean Sweep Trio.
- After use they last up to 28 days.
- They are very easy to use. You handle one product rather than up to 4.
- There is less chance of resistance.
- You can legally use some of these on the home lawn.
- Be aware of issues with thatch build-up that occur with some actives.
To help with disease identification, here is a chart that shows common turf diseases. This Gilba blog is also be useful as it discusses approaches to manage turf diseases.
Better Disease Control With Turf Combination Fungicides.
The increase in the results from fungicide treatment is one of the major benefits of combination fungicides.
To put it simply, two or more active ingredients are likely to kill a pathogen better than if you use them alone.
Once you apply these to turf, the fungicide is subjected to several forces that degrade the active. Rainfall, irrigation and mowing will actually only remove only a small amount of the fungicide.
Instead, soil microbes that inhabit thatch and leaf surfaces degrade them. These microbes attack the turf chemicals and break them down into products they use for their own nutrition and growth.
Even chemicals that work by penetrating the leaf surface (aka systemic) aren’t safe from attack. Turf responds to these by dispatching enzymes that neutralise them.
New Actives For Australia.
Turf combination fungicides such as Indigo Clean Sweep Trio and Enclave (Adama) contain thiophanate-methyl. This is a new active in Australia for turf disease control that has strong curative & preventative performance. It is also an excellent brown patch fungicide and so one of the best fungicides for lawns.
Thiophanate-methyl is taken up by the roots and leaves of turf and is a member of the benzimidazole group. It is classed as being in FRAC Group 1 and is a tubulin inhibitor. Its Mode of Action is the inhibition of microtubule assembly. Here is a presentation on Clean Sweep.
28 Days Control With Turf Combination Fungicides.
All of these products last for up to 14 to 28 days against a wide range of turf diseases.
Convenient Handling.
When you can treat several diseases at once, these products reduce application time. Since the pre-packaged chemicals are compatible, they also reduce some of the uncertainty that relates to this.
Less Resistance With Turf Combination Fungicides
Each product is a combination of at least two groups. This means that you can reduce the need to rotate mode-of-action groups. Our guide to fungicide chemical groups helps explain this in more detail.
When you use a pre-mix, it gives you the peace of mind that the fungicides are compatible with one another. In fact, the active ingredients can sometimes work against the same disease.
The development of most turf combination products seems to have been in order to increase the activity spectrum of a single fungicide. This is another reason why these are the best fungicides for lawns.
But what about DIY Mixes?
If you mix your own brews it may help to manage resistance. However, you increase the chances of turf damage. Besides this, some actives, such as thiophanate-methyl are only available with a turf registration in these products.
The use of turf combination products reduces the amount of time that each active is exposed to the environment. This limits the selection pressure on pathogens that are resistant to each fungicide.
Combination products offers an excellent resistance management tool where resistance risk is high. This tends to be the case with the turf diseases anthracnose, dollar spot, and fusarium sp.
Their high degree of effectiveness reduces the chance of resistance even at these lower use rates. There is plenty of evidence that fungus cells can change when under stress.
Sublethal doses cause a degree of stress that can cause a variety of changes, such as fungicide insensitivity mutations. The frequency of these mutations decreases if turf combination fungicides makes these sublethal doses more lethal.
Some Are Legal to Use in the Home Lawn.
Exteris Stressgard, Interface Stressgard (both Bayer) and Clean Sweep are legal to use on lawns. This is another reason why these are the best fungicides for lawns.
Jerry Spencer
Graduated from Newcastle University with an Hons Degree in Soil Science in 1988, Jerry then worked for the Sports Turf Research Institute (STRI) as a turf agronomist before emigrating to Australia in 1993.
He followed this by gaining a Grad Dip in Business Management from UTS. He has worked in a number of management roles for companies as diverse as Samsung Australia, Arthur Yates and Paton Fertilizers.
He has always had a strong affinity with the Australian sports turf industry and as a result he established Gilba Solutions as an independent sports turf consultancy in 1993. Jerry has written over 100 articles and two books on a wide range of topics such as Turf Pesticides and Nutrition which have been published in Australia and overseas.