Stopping Turf Disease with UV-C Treatment

How UV-C treatment helps groundskeepers to combat turf diseases – without chemicals

Higher temperatures, changing weather conditions, and the increasingly intensive use of sports turf pitches favour the growth of pathogens. Algae, fungi, and turf diseases such as snow mould, dollar spot, and red tip are increasingly occurring in combination, increasing the need for targeted prevention and control. Until now, many groundskeepers have relied on chemicals to combat turf diseases. However, the European Commission wants to reduce the use of chemical pesticides by 50 per cent by 2030. With its scientifically developed UV-C treatment, Rhenac offers an efficient and environmentally friendly solution.

Ultraviolet light kills microorganisms

UV-C light in the spectral range of 100 to 280 nanometres is the shortest wavelength range of ultraviolet light. In nature, this range is filtered out of the sun’s rays and does not reach the earth. However, artificially generated UV-C light is used in many areas, as targeted irradiation triggers a photochemical reaction: the chemical bonds of microorganisms are broken, and this damage to the RNA or DNA causes microorganisms such as viruses or bacteria to be unable to reproduce. They die off in a very short time and without any chemicals. This is why UV-C treatment has long been used to disinfect objects and surfaces in hospitals, to disinfect indoor air, and to treat water.

Research series on the ‘grey leaf spot’ pathogen at TU Munich

Rhenac has awarded the Technical University of Munich a research contract to better understand the development and symptoms of turf diseases. In a series of research projects, scientists have been working intensively on the pathogen grey leaf spot (Pyricularia grisea = Pyricularia oryzae = Magnaporthe oryzae). For a few years now, this pathogen has been increasingly active in spring and autumn on sports turf areas and particularly attacks turf of the two Lolium species L. perenne and L. multiflorum as well as tall fescue (Festuca arundinacea). The symptoms: greyish discoloured leaf spots, which can also appear somewhat brownish depending on the host plant species and stage of infection. The increasing infestation is presumably favoured by the growing conditions in modern stadia. These include an above-average nitrogen supply, particularly in the pathogen’s early phase, activation of the roots through soil heating, year-round exposure to light, low air exchange, and daily tilling of the turf – and thus a change in stress tolerance.

In the experiments, the scientists investigated whether it is possible to counteract the outbreak of diseases such as grey leaf spot with the help of UV-C treatment. The spread behaviour of fungi was investigated using mycelium (fungal network) and the development of fungal spores, the effect of different dosages and irradiation times, and the reaction of phytohormones.

The results of the test series confirm the effect of UV-C treatment:

• Mycelium growth is inhibited by direct and dosed UV-C treatment.
• Spore formation is also inhibited – and even stopped – with regular application.
• The effects depend on the irradiation intensity and duration: Simply structured microorganisms such as bacteria can be treated with a low dose without any problems. Fungi and spores require larger amounts of energy and several irradiation processes.
• Targeted use of UV-C treatment stabilises the cell walls: the plant forms a mechanical barrier and becomes more resistant to pathogens and germs.
• Regular use of UV-C treatment boosts the plant’s “immune system” and strengthens secondary plant substances – the plant’s own compounds that control its growth and development. This vitalises the turf and helps prevent further outbreaks of disease.

Mobile UV-C treatment system

Based on these scientific findings, Rhenac has developed a mobile UV-C treatment system for sports turf. The UV-C Pitch Disinfection Front Loading System is moved across the turf using a turf tractor.

Flexible
The exposure unit can be extended to a length of up to 6 metres as required. It draws its power either directly from the tractor or from its own power unit. The intensity of the lighting is regulated by adjusting the height of the lighting unit.

User-friendly
The correct moving speed of the device is indicated acoustically. If it is moving too slowly, a signal sounds in slow succession; if it is moving too fast, a signal sounds in quick succession.

Safe
The system is equipped with a foam spraying device to mark the lane. This prevents the respective turf lanes from being repeatedly exposed to UV-C light.

Precise dosing of UV-C light based on measurement data

Early identification of turfs at risk is important for the targeted control of turf diseases. This is why Rhenac has developed the Quality Analyser, a small measuring device that is attached to the mobile Pitch Disinfection Front Loading System and continuously measures data such as UV stress markers, photosynthesis markers, and light-cold-dry stress. By analysing this data, emerging disease can be predicted even before the first symptom appears: the endangered turf area can be treated preventively with UV-C light. Based on the regularly measured data, Rhenac also determines the required light intensity and irradiation duration.

Advantages of UV-C treatment

• Reduction in chemicals: UV-C treatment significantly reduces the use of chemical pesticides.
• Effective control of turf diseases: algae, fungi, and other microorganisms are specifically killed by UV-C light.
• Improved turf “immune system”: the turf is revitalised and further outbreaks of disease are prevented.
• Scientific basis: intensive research at the Technical University of Munich has proven the effectiveness of UV-C technology.

Optimum function in a networked system

The mobile UV-C treatment offers an effective solution for combating turf diseases by specifically killing micro-organisms such as fungi and bacteria and strengthening the turf’s “immune system”. For optimum results and a healthy turf all year round, this system should be combined with other innovative technologies from Rhenac, such as lighting and maintenance systems. The synergies of this comprehensive care concept not only protect against disease but also improve the quality and aesthetics of turf.