Turf combination fungicides. 21

In recent years there has been an increase in the market of Australian turf combination fungicides. With the launch of Clean Sweep Trio from Indigo Specialty, we think it is time to put some information together on turf combination fungicides. The free Guide to Turf pesticides has more information relating to specific diseases these control. Combination fungicides are fungicides for turf that include more than a single active ingredient and offer a number of benefits over straight fungicides. These are often registered for use in the home garden for turf disease control. The key ones are:

• An increased spectrum of disease control;
• Completely new fungicide active ingredients for the Australian turf market. This is the case with Lexicon Intrinsic and Clean Sweep Trio ;
• Longevities of up to 28 days after application;
• Convenience of handling one product rather than up to 4;
• A reduced likelihood of disease resistance occurring and finally
• Some of these can be legally used by home lawn owners.

To help with disease identification, here is a chart showing turf fungal diseases. This Gilba blog may also be useful as it discusses approaches to managing turf diseases.

An increased spectrum of disease control using turf combination fungicides.

The increase in the effectiveness of a fungicide treatment is one of the major advantages of combination fungicides. To put it simply two or more active ingredients are more likely to kill the target pathogen than if applied individually.

Once applied to turf, a fungicide is subjected to a number of forces that will remove or degrade the active ingredient. Rainfall, irrigation and mowing remove only a small amount of fungicide. Instead naturally occurring soil microorganisms that also inhabit thatch and leaf surfaces degrade the vast majority. Microbes rapidly attack pesticides and break them down into products useful for their own nutrition and growth. Also, chemicals that work by penetrating the leaf surface (aka systemics) aren’t safe from attack as turf responds to pesticide applications within their tissue by dispatching enzymes that neutralise these alien substances.

Completely new fungicide active ingredients for the Australian turf market.

Turf combination fungices such as Indigo Clean Sweep Trio and Enclave (Adama) contain thiophanate-methyl. This is a new active in turf disease control that also delivers strong eradicant, curative & preventative performance. Thiophanate-methyl is absorbed by the roots and leaves of turf and is a member of the benzimidazole group of fungicides. It is classified as being in FRAC Group 1 as it is a tubulin inhibitor fungicide. Its Mode of Action is the inhibition of microtubule assembly. Presentation on Clean Sweep Trio.

Longevities of up to 28 days after application using Turf combination fungicides.

All of these products give from 14-28 days control against a wide range of turf diseases.

Convenience of handling one product rather than up to 4.

By treating several diseases at once, these solutions reduce application time. Since prepackaged goods are compatible, they also reduce some of the uncertainty related to fungicide compatibility.

A reduced likelihood of disease resistance occurring when using turf combination fungicides

Since each product is a combination of at least two groups, you might be able to reduce the need to rotate between mode-of-action groups. Our guide to fungicide chemical groups will help explain this. 

Using a pre-mix gives you the peace of mind that the fungicides are chemically compatible with one another. In fact the active ingredients can all sometimes be useful against the same disease. The development of most turf combination products seem to have been in order to increase the activity spectrum of a single fungicide.

But what about DIY mixtures?

Yes, creating your own mixtures may be useful in managing resistance, but you are increasing your chances of causing turf damage. Besides this, some actives, for example, thiophanate-methyl are only available with a turf registration in these combination products.

Using turf combination products reduces the amount of time that each active ingredient is exposed to the environment. So this limits the selection pressure on pathogen strains that are resistant to each particular fungicide.

The use of combination products offers an excellent resistance management strategy where resistance risk is high for example turf diseases anthracnose, dollar spot, and fusarium sp).

Furthermore, this improved effectiveness reduces the chance of resistance occurring even with these lower fungicide doses. 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 alterations, such as fungicide insensitivity mutations. The frequency of mutations will decrease if turf combination fungicides makes these sublethal doses more lethal.

Some of these can be legally used by home lawn owners.

Exteris Stressgard and Interface Stressgard (both Bayer) and Indigo Clean Sweep Trio can be used in home garden situations on turf.