Microdochium patch disease control strategy starts in August

By Alistair August 11, 2024 07:51

By Henry Bechelet, Technical Sales Manager, ICL

Microdochium patch disease will no doubt be on all our minds for the rest of the year. It is an extremely damaging disease that could strike at any time. If we want to get through the autumn and winter in good shape then we will need to employ every method available to us to slow down its development or achieve control.

Causes and conditions for Microdochium patch disease

Microdochium patch disease is caused by the fungal pathogen Michrodochium nivale and it is constantly lying in wait to develop at any time given adequate moisture and cool temperatures. If conditions are suitable then it can develop very quickly (initially unseen) and potentially spiral out of control to cause widespread damage, especially to golf greens.The damage commonly occurs in the autumn and winter when recovery growth might be months away. Microdochium patch disease prevention and control is one of our top agronomic priorities for the year.

Managing Microdochium patch disease

We know from our experiences that we can manage this disease to limit the level of damage. But to achieve this we need to be fully on our game. First of all we need to ‘be alive’ to those climatic factors that favour the development of the disease. Cool and wet conditions are the key drivers.

This is where a resource such as the Syngenta Turf Advisor app can bring us some real value because it factors our local climatic conditions into disease prediction models that then calculate the level of risk of an outbreak developing. You will also need to factor in your own site considerations (level of shade, top-dressing, intensity of maintenance and so on) to get a truer reflection of the risk, but this is something we have always done.

Monitoring and early detection

Alongside forecasting resources, we will need to keep a close eye on the situation. Careful monitoring and feedback from all the greenkeeping team is essential. We should always be looking for the early signs of discolouration, which can be a sign of infection and also focus on those indicator greens that tend to show that bit sooner.

Preventative measures

Obviously, we don’t want to be seeing any disease activity and so we put together a plan of action that aims to prevent it. We start by considering those factors that favour the development of the disease and then managing them in such a way to reduce their influence.

Reducing leaf wetness

The biggest influencing factor for the development of Microdochium patch is leaf wetness and so we need to find ways of reducing this. Turf soil surfactants should still be deployed to reduce irrigation requirements.

We do have good dew dispersant technologies but they don’t tend to be deployed at this time with active growth occurring because they can quickly be mown off.
At this time we will need to employ switching / brushing / turf ironing and so on as required to remove dews and reduce that period of leaf wetness.

Maintaining turf health

Turf health is also hugely important in terms of creating a less conducive environment for the development of Microdochium patch disease.

In terms of nutrition, we are just trying to set the right balance of not too much nitrogen or too little. The actual levels of nutrition that you will need will be influenced by a large number of factors (intensity of maintenance, rootzone type and general environmental conditions and so on) but I would say that as a general guide I would be looking to supply in the region of 2-3kg of N/week in August but this might actually be more or less depending on the situation.

Nitrogen source considerations

An important consideration at this time would be the source of nitrogen and generally we would advocate using slow release granular fertilisers (in our case using formulations containing Methylene urea).

The Sierraform GT K-STEP 6-0-27 +TE always does a great job in its own right at this time and it can be applied at low rates (20 g/m2) without any speckling. The Greenmaster Pro-Lite ‘Autumn Mg’ 6-5-11 +3MgO has a similar release pattern and would also be a common recommendation at this time if P and K are needed to support an overseeding programme.

Greens renovations

Greens renovations are commonly scheduled for August to take advantage of the good levels of growth at this time. If an intensive programme is taking place and a high level of top-dressing being applied then the risk of Microdochium patch disease would rise especially if conditions turn cool and damp.

This would greatly increase the risk of attack and a preventative fungicide might be needed.

Use of fungicides

This brings us to the use of fungicides, which are a central part to any autumn ITM plan.

The need for a fungicide treatment will depend on the level of risk / disease activity but if a heavy renovation programme is scheduled then a preventative application might be wise. In terms of what to use, ‘FR321’ is a one box solution from Syngenta containing both Heritage and Medallion TL (along with Ryder) so it is a really strong broad-spectrum tank-mix.
Generally, however, if we have everything in place and the climatic conditions are not so conducive to attack, then a preventative application may not be needed until September.

Starting the control strategy

So, August is the start of our Microdochium patch disease control strategy that we will be running through autumn and winter.

This is a crucial programme of work if we are to maintain smooth and true putting surfaces for play. We will need to keep a close eye on those climatic factors and our focus should be on reducing leaf wetness, maintaining turf health and thinking about the intensity of surface preparations. If renovations are scheduled and conditions are favourable for the disease then we might need to factor in a preventative fungicide application.

There is always plenty to think about but it’s important that we go into autumn with our ITM plans already fully up and running.