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Winning the battle against Spring Dead Spot

Bowls
30.01.2018

Treating a bowling green infected with Spring Dead Spot (SDS) can be a notoriously difficult task – especially once the disease gets out of hand.

The challenge lies in the disease’s cycle. SDS often has the competitive advantage over surrounding turf, as it becomes active in winter when the temperature drops to around 15°C and Couch Grass grows at its slowest. Once spring hits and the grass breaks dormancy, the results can be catastrophic. The roots of affected plants become severely rotted, and circular patches of bleached grass appear on the turf. Grass regrowth is slow, which means the patches often remain barren or become filled with weeds.

How to effectively manage SDS

‘Prevention is better than cure’ is a popular saying for a reason. The most effective weapon against SDS is ongoing management: a strategy that combines good cultural practices with an effective fungicide schedule.

Practices that can help prevent SDS infection on the bowling green include:

  • fertilising the bowling green in the late summer/autumn season – this allows the plants to store carbohydrates over winter so the turf can break dormancy when temperatures rise in spring

  • managing fertiliser levels, as heavy applications of nitrogen in the late summer can often increase SDS severity the following spring

  • ensuring good drainage, as SDS thrives in moist soil

  • maintain a low level of thatch – ideally below 1.1 cm thickness – to discourage disease

Cultural practices alone, though, aren’t enough. A preventative fungicide program is also crucial to keeping fungal diseases like SDS at bay and ensuring your bowling green looks its best. To avoid a ’hit and miss’ approach and ensure effective application, here are three tips when it comes to implementing your fungicide program:

1. Provide as much active ingredient as possible in the plant

A successful preventative program must deliver as much active ingredient as possible into the plant to provide long-term protection – usually up to 4 applications in late summer and autumn. Syngenta’s broad spectrum fungicide, VELISTA, is a good option, designed to ‘lock’ into the root system without translocating throughout the plant when it is washed into the root zone.

2. Irrigate before the application dries on the leaf

To protect your green over the winter months, make sure you irrigate the turf before the fungicide has time to dry on the leaf. If a fungicide is left to dry, the active ingredient will move into the leaf rather than being taken up by the plant’s roots when it is eventually washed into the root zone. This reduces the fungicide’s effectiveness, leaving turf vulnerable to diseases like SDS.

3. Rotate your fungicide

It is a good idea to rotate between fungicides with different modes of action, as this helps prevent disease resistance. While most turf managers are heavily reliant on the Qol or Strobilurin Group 11 fungicides such as Syngenta’s HERITAGE MAXX, VELISTA features a new mode of action: Group 7 SDHI. This makes VELISTA an excellent rotational partner which helps minimise risk of resistance and extend the usable life of many existing and future chemistries.

Suggested SDS programs:

Spring Dead Spot Control Options

 

JAN

FEB

MARCH

APRIL

Application rate

Irrigation

 BANNER MAXX

X

X

 

 

700 mL

YES

 HEADWAY MAXX

X

X

 

 

630 mL

YES

 HERITAGE MAXX

X

 

X

 

840 mL

YES

 VELISTA

 

X

 

X

210 g

YES

 

Control SDS with VELISTA

VELISTA is a powerful broad spectrum fungicide that helps you build a strong defense against SDS and other fungal diseases with ease.  It has no phytoxicity or growth retardant effects, making VELISTA suitable for late summer applications.

For more information on SDS prevention, please talk to your local Syngenta turf specialist or contact us at greencast.com.au.

You can also download our Bowling Green rate conversation chart or the Greencast app, which keeps up-to-date labels, tank mixing calculations and read-to-go spray records at your fingertips.