Keep winter diseases out,
while saving on energy

Agronomy expert Dr. Irene Vroegop on the effect of temperature on disease pressure.

Gray leaf spot on turfgrass football pitch

With the World Cup in full swing and (most of the) club football temporarily on hold, clubs are minimizing the use of their lighting units as much as possible to save energy. And rightfully so. Microdochium patch, also known as pink snowmold, is a disease that thrives in low temperatures. Usually groundsmen use their grow lights and undersoil heating to add heat, which increases grass growth and subsequently decreases the risk of winter diseases. But what ways are there to increase plant resistance while keeping energy usage to a minimum? And what should you look for in identifying this type of grass disease?

The effect of grow lights on the occurrence of grass diseases

Dr. Irene Vroegop: “Let me start off by saying that we do not see unusually high incidents of pink snowmold in the stadiums yet. The occurrence rate of this type of grass disease is in line with what we forecast for the time of year. We generally see cases of pink snowmold occur in the stadiums when temperature drops below 10 °C, which is normal this time around for countries in the northern hemisphere . Whether you choose to use your HPS grow lights or LED with infrared or not, influences the air and soil temperature inside the stadium, and thus affects the conditions for grass diseases.

As you can imagine, soil and air temperature in the stadium will less likely drop below 10 °C with the HPS grow lights or LED with Infrared on, than when they stay off. The heat that’s radiated from the units results in a higher air and soil temperature, creating an unfavourable situation for a grass disease like pink snowmold to contaminate the playing field. In addition, the grow lights keep the grass plant active, and therefore more grass disease resistant. But if you’re looking to save on energy, there are other ways to fend off grass diseases.”

To summarise, if you keep the grow lights on, soil and air temperature are less likely to drop below 10 °C because of the heat radiated by the unit, the grass plant stays active and there is less chance of pink snowmold infecting the pitch. Of course, outside temperature plays an important role. If temperatures are just above freezing or lower, soil and air temperature will drop below the 10 °C threshold, despite the grow lights. However, there are more ways to prevent winter diseases.

A grass playing surface infected with pink snowmold.

Spot the pink snowmold

  • Preferred temperature: 0 – 10 °C
  • Symptoms: Circle, Patch, Spot, Irregular, Brown, Orange
  • Time of year: September until April
  • Turfgrass species: Pretty much all turfgrass species

So, what if you’ve decided to keep the grow lights switched off as much as possible for sustainability and financial reasons, but want to keep the chance of pink snowmold contaminating the playing field as low as possible? What measures can you take?

Monitor your pitch data

“Pay close attention to your pitch data,” Irene emphasizes. “From the data displayed by the SGL Portal, you will be able to tell if conditions, like soil and air temperature, are favourable so that you need to be alert for pink snowmold. If you make use of the Assist module ‘disease forecast‘, the Portal will calculate exactly which diseases are likely to occur and when and how often it is recommended to use the UVC180, should you have this sustainable fungal disease treatment device available at your club.

It is also recommended to keep the leaf wet period as short as possible. Because just like temperature, humidity is an important variable that influences the likelihood of pink snowmold to infect the playing field. When humidity levels exceed 85% and air temperature is below 10 °C, you’re at risk for pink snowmold to occur. You can lower the humidity levels by sweeping the dew off of the pitch in the morning for instance.”

With energy prices higher than ever, it is beneficial and recommended to save on energy these months. However, without using grow lights when there’s no play, it’s even more important to monitor the conditions carefully and apply cultural practices to keep your pitch healthy and strong for when competition starts again.

It can be tough to distinguish one grass disease from the other, but with the help of the grass disease poster, you’ll be able to recognize the symptoms quickly and take timely action to keep your pitch disease free.

About Dr. Irene Vroegop

Irene is agronomist and turfgrass disease expert at SGL. Her degree in biology with specialization in Environmental Biology, and PhD research on plant-microbe Interactions, form a profound basis for her research and advisory role within the SGL agronomy department. As part of the SGL Assist team, Irene supports groundsmen on a daily basis to achieve a top quality pitch throughout the year.