Top Tips: Fusarium management
The greens at Maesteg Golf Club were dominated by weak grasses, making them highly vulnerable to Fusarium. Deputy Head Greenkeeper James Matthewman and his manager recognised this as an opportunity.
Instead of fighting the disease, we allowed it to run its course. Because Fusarium specifically targets weak grasses such as Poa annua, this strategy eliminated the undesirable species, giving us a fresh start for a complete renovation and the chance to establish stronger, more resilient grasses such as fescues and bents.
The greens became alarmingly thin, but we used that bare ground to our advantage by successfully seeding better grasses such as fescue and bent. I can’t really recommend this extreme method to others, however, as it’s a huge gamble.
Poor conditions often attract heavy criticism from members, which in turn adds considerable mental stress. The smarter approach is to use preventative sprays to control the disease while gradually increasing the proportion of desirable grasses.
Can you stop Fusarium before it starts?
Yes, you can - but it is exceedingly difficult, as outbreaks can appear suddenly. This makes prevention essential. The following methods can help reduce the risk of a serious outbreak:
Cultural prevention methods
(Focus on reducing moisture and stress)
Moisture management
- Dew removal: Regularly remove dew from the turf surface by switching (using a long, pliable rod or bamboo cane) or brushing, especially in the mornings. Rolling the greens can also be effective. This disrupts the fungal germination cycle by reducing leaf wetness.
- Improve airflow and drainage: Prune back overhanging trees or shrubs to increase air movement and promote rapid drying. Improve soil aeration and drainage through practices such as spiking, hollow- or solid-tining, and regular sand topdressing to dilute thatch.
- Irrigation scheduling: If irrigation is necessary, water deeply and infrequently, ideally in the pre-dawn or early morning hours, to minimise the duration of leaf wetness overnight. Avoid overwatering or light, frequent irrigation.
Nutritional balance
- Avoid excessive nitrogen: Do not apply high doses of nitrogen fertiliser, especially in late summer or autumn, as this encourages lush, soft growth that is highly susceptible to the fungus.
- Maintain potassium and micronutrients: Ensure adequate levels of potassium and micronutrients, as high potassium levels can help suppress the disease and strengthen the turf’s cell walls.
Thatch management and aeration
- Minimise thatch layers through aeration, scarifying, and topdressing. Thatch retains moisture and provides a material for the fungus to thrive.
- Aerify compacted soils to improve drainage and root growth.
Grass species selection
- Overseed or select grass varieties that are less susceptible to Fusarium patch, such as certain cultivars of bentgrass or fescue, rather than highly susceptible species like annual meadow-grass (Poa annua).
Key weather challenges
Fusarium thrives when the weather creates an ideal “disease triangle” of susceptible host, pathogen, and favourable environment.
The specific conditions that make prevention and control more difficult are related to prolonged moisture and cool, mild temperatures:
- Prolonged leaf wetness: The fungus requires surface moisture for its spores to germinate and infect the grass. Persistent rain, high humidity, and morning mists that are slow to clear - especially on overcast, still days - keep the grass blades wet for extended periods, providing a continuous window for infection. This is particularly difficult to manage culturally, as dew removal becomes a daily battle.
- Optimum temperatures: The fungus is most active in cool, mild conditions above freezing. The disease is most common in autumn, winter, and early spring. Milder winters and extended periods of cool, wet weather prolong the infection season, forcing greenkeepers to maintain control efforts for longer periods.
- Low light and overcast conditions: Shorter daylight hours and heavy cloud cover in autumn and winter reduce sunlight and air movement, which further slows the drying of the leaf surface, intensifying the humidity and moisture challenge.
- Snow cover (pink snow mold): When a prolonged layer of snow falls on unfrozen ground, it creates a constant, mild, moist environment beneath the snow blanket. This environment is extremely conducive to the fungus, which can cause considerable damage before the snow melts.