Combatting Turf Stress

How time, investment and science are allowing Signature Xtra and Exteris Stressgard to combat stress in turf.

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Summer Drought

Since 2002 the UK has seen the ten hottest summers on record, and in the last decade (2010-2019) the average temperature has been 0.9°C higher than the long-term average (1961-1990), according to the Met Office. These increased temperatures are leading to a higher stress burden on turf.

Dr Colin Mumford, technical support manager at Envu, says high traffic, exceptionally hot temperatures and longer lasting droughts can cause a decline in turf quality and the aesthetics of professional natural grass playing surfaces. Fine turf surfaces such as golf and bowls greens are particularly susceptible to a detrimental impact on the playability of these surfaces during prolonged hot, dry periods.

Extensive STRI independent trials, lasting two years and completing in 2020 showed that the damaging effects of heat stress can be reduced with applications of Envu’s Signature Xtra (for use in Ireland) and Exteris Stressgard.

The trials found that those plots treated with - Signature Xtra or Exteris Stressgard between June and August had the greatest turf density and a 10% better live ground cover, compared to the untreated plots.


So, how do these products work?

Throughout the year turf experiences a number of stresses. Each season brings its own unique environment, from days of intense sunlight and high UV radiation in the spring and summer, to damp shorter days in autumn and winter. These conditions contribute towards ideal environments for a wide range of fungal diseases to thrive and attack.

Luckily the formulation technology in Envu’s products is the result of years of R&D and investment, working to ensure that turf receives the protection it needs.

Both products lead the way in chemical makeup. Exteris Stressgard, for example, includes a succinate dehydrogenase inhibitor (SDHI).

The SDHI name is derived from the fact the product interferes with a molecule in the electron transport chain. In order to make energy, fungi move electrons through a chain of different molecules. At the end of this chain ATP is produced, a molecule that all living organisms use as an energy source, Exteris Stressgard halts this process, which leads to the death of the attacking fungi.

Signature Xtra, which is available in Ireland, is the only true systemic fungicide (Fosetyl-aluminium) and is the newest mode of action for the industry in recent years.

Colin Mumford says, “It is important that turf managers rotate the different modes of action that are available to them to prevent resistance building up within the pathogens. Signature Xtra and Exteris Stressgard have different modes of action, and give you control over your resistance management, disease and stress management, plant health, colour and density.”

Signature Xtra and Exteris Stressgard are authorised fungicides that work directly on pathogens. Programmes incorporating them have also been shown to increase chlorophyll content, improve photosynthesis, encourage stronger, more vigorous plants with robust roots, as well as protect against harmful UVA and UVB radiation. These benefits promote stronger plant health, enabling the turf to better withstand attack from turf disease pathogens.


And, how did they come about?

It’s useful to highlight the size, scale and colossal investment chemical companies make into research and development of new products. It’s nothing short of mind blowing- taking up to 8-12 years and between one to two hundred million pounds to get a new active ingredient through the system.

Whilst the Environmental Science business is being divested to Cinven this year, the products currently coming out of Envu have been developed at the headquarters in Monheim, Germany and the USA by a dedicated team, working to find solutions for the turf and amenity sectors. This will continue after the divestment too.

The process of a new product usually begins with listening to the end user and then searching for the relevant formulation of ingredients and substances taken from a huge library where over eight million base substances are stored. Following the active ingredient discovery and characterisation, a series of other activities take place including safety studies, intellectual property documentation, pest targets, use rates and patterns determination (including field testing), formulation determination, registration, marketing and manufacturing.

Research efficiency is vastly increased by the use of modern computer simulation (modelling tools) and sophisticated analysis to determine the structure and purity of potential new chemical compounds. This is only made possible through the availability of advanced networked information technology to process the huge amounts of data generated.

Chemical compounds then get sent to a number of laboratories where their spectrum of action is thoroughly investigated for fitness of purpose.

Strict testing criteria, which includes multi-year internal and external greenhouse and field testing mean that, after 8 to 12 years, only one in about 100,000 compounds synthesised finally develops into a commercial turf or amenity product.

A turf and amenity product can only be granted marketing authorisation if it has passed all the tests to show it will not pose an unacceptable risk to humans or the environment when used as directed. This includes the ability for an active ingredient to break down in the soil, rather than leach into natural water courses and ground water.

Because of this ongoing investment new products will continue to become available and will give greenkeepers the tools they need to provide the excellent playing surfaces that we all enjoy.

To discover more about the formulation technology involved in Signature Xtra and Exteris Stressgard or about the STRI trials, download Envu’s informative guide for Signature Xtra here and for Exteris Stressgard here.

As featured in GreenKeeper International Magazine.

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