Disease, Pests & Weeds

In this section we will cover some of the problems that nature throws up and some problems that we bring on ourselves. There is a lot of information on disease, pests, and weeds at our fingertips through internet, different people will take different approaches, there are plenty of greenkeeping pages on Facebook that have valuable first-hand accounts of how other course managers are dealing with these problems. I can only speak about what I have experienced and what I have learned in college and from books.

One thing I cannot emphasis enough is how, the healthier a plant/turfgrass is, the less chance it will become infected by disease or weeds and if it does, the healthier it is the quicker it will recover with the correct action taken. Also, how important it is as stated before, to keep the turfgrass as dry as possible for as long as possible.

Everything we have covered so far from, the management of the lower and upper profile, to aeration to de-thatching, to de-dewing the greens every day, from top dressing to accurate application of fertiliser, and from heights of cut to blade and cylinder maintenance, is all towards having a healthy plant/turfgrass surface with very little stress. We as course managers, as we have seen stress the plant sometimes needlessly to obtain the perfect surface, which in turn invites the problems we are about to cover. 

Any of the chemicals named below are still available to the best of my knowledge but may recently have been removed from the active list, or may only be available in the UK, so be sure to contact your chemical supplier for further information.

On golf courses an IPM (Integrated Pest & Disease Management) is used to determine the action to be used. The considerations for developing an IPM programme are:

Monitoring- Identification is vital for success. Watching for colour, thinning, patches and other signs of damage. Disease can be more predictive because of changes in climate.

Predicting/Forecasting- Websites can help predict using temperature and moisture readings. The length of time turf is wet at a particular temperature is vital.

Thresholds- This is more to do with aesthetics. How long or far can you allow a disease or pest to infect your turfgrass before you act. Do you have the finances to apply preventative measures (this action would be against an IPM) or do you wait and see how bad it gets until you take curative or eradication action? Another example can be to monitor a pest. Soaping an area, the find the number of larvae, then compare this to previous years and then you have you answer of whether to act or not.

Cultural options- Are you under or over applying Nitrogen? Over may result in Fusarium Patch or under may result in Red Thread. If you have bent and fescue turfgrass over application of Nitrogen can increase encroachment of Poa Annua/Meadow. Excessive mowing, is the height of cut too low, leaf wetness, is turf being de-dewed? most pathogens require leaf wetness for infection. Is thatch a problem? if so, has aeration, de-thatching and topdressing been performed enough? If not proceed with these first before chemical option.

Chemical/Biological option- This should be the very last resort. There are a few options available, but year on year environmental agencies are reducing the numbers by removing chemicals from the market. There are three main groups of fungicides, Propiconazole, Fludioxonil and the Strobilurins group which includes, Azoxystrobin, Pyraclastrobin and Trifoxystrobin. Iprodione was extremely popular for years but was taken of the last a short while ago.

Evaluate/RecordRecord everything, the problem, when and where it was first noticed, the climate, what threshold you set, your cultural maintenance and finally if you needed chemical or biological action. Then decide if you need to change your maintenance programme to stop a repeat of the problem in the future.


There is an abundance of articles on the internet about turfgrass diseases with everything being covered from preventative to curative measures. What I will do here is cover the basics, name of the disease, symptoms and signs of the disease and possible actions. What I will say is no matter what action is given as regards chemical options, the first thing that must be done is to implement the IPM from above. You are always taking a chance when spraying chemicals and the environmental agencies will come down hard on you, if you are found to be in the wrong or you have applied a chemical without proper spraying qualifications, so make sure you are aware of the law for you and your club’s benefit.

Before going through a few diseases, I just want to quickly go through fungicide activity and types. There are three types of activity.

Preventative-Best applied before periods of high risk. Stops spore development on the leaf surface to prevent infection.

Curative-Before symptoms are visible. Stops early pathogen development inside the plant. Applied at periods of high risk when infection could have occurred, for example if a warning is given.

Eradicant- Apply when first signs of infection are identified. Stops pathogen development when disease symptoms are visible. Prevents further spread.

Types of Fungicide:

Systemic- Readily absorbed and moved within the plant. Suited for times when turf is growing actively. Movement within the plant means it will stay around longer including when plant is being mowed. This is done through the Xylem. Some systemics are absorbed through leaves only and other through crown and roots. Heritage is a good example of a systemic fungicide.

Contact- is a one-hour rain fast meaning it will not be washed of in rainfall or irrigation. When grass is cut it is gone. Good in cold weather but coverage is vital as there is no spread. It is used frequently when grass is growing more slowly. Used to target specific disease. Medallion TL is a good example of a good contact fungicide as it bonds onto the leaf wax layer.

Another important thing to factor in is that plants can build up a resistance to the active ingredients of fungicides, particularly if you continue to use the same one. Therefore, it is important to understand the difference between systemic and contact and to try mix and match products to avoid a resistance to a certain product.

Fusarium Patch (Microdochium Nivale)

Easily the most common we come across in pitch and putt. This is a fungal turf disease. Meadow/poa annua grass species are most susceptible.

Usually seen in Autumn, winter and on occasions in March during periods of mild, wet weather. Will appear when temperatures are 4-10 degrees. Optimum conditions are high atmospheric humidity and air temperatures of 0-7 degrees. With extended leaf wetness outbreaks may occur up to 18 degrees so has a wide temperature range.

Symptoms- are small circular reddish/brownish patches. They first as small and then develop it to bigger patches. On low cut turf, patches may form with water-soaked black outer margin.

Signs- maybe a dull pink/white (fluffy) Mycelium may develop. This will be noticeable in early daylight hours. Extended leaf wetness will help in larger areas being infected.

Spreading- High Nitrogen inputs which promotes succulent growth can increase turf susceptibility. Poor drainage can also encourage it.

Cultural control- managing Nitrogen levels, improve drainage with aeration and topdressing, reduce shading, mow when dry, remove morning dew and minimise irrigation and just de-stress the turf in general.

Chemical control- Fungicides are used. Contact your local supplier to see what products they have available but keep in mind there are very few effective fungicide active ingredients left to call upon.

Typical case of Fusarium. Ref.Dreamstime.com
Fusarium with the white Mycelium Ref.Dreamstone.com

Anthracnose (Colletotrichum Graminicola)

Is a fungus most commonly found in Meadow/Poa Annua grass in Ireland and the UK. The pathogen can occur in two forms, Foliar Blight (on the leaf) and Basal Rot (rot of the crown, stem base and roots). It is often mistaken for drought. It is the second most common disease on golf courses.

It is likely to attack stressed Meadow/poa annua grass species. Surface will lose its trueness. As grass coverage is lost, this will encourage weeds.

Symptoms-(Foliar) there will be reddish/brown leaf lesions, leaves will then turn yellow and finally light tan colour and may die. May kill plants in irregular patches from 5cm to several metres across.

Symptoms- (Basal Rot) a water-soaked stem lesions will appear first. The lesion will darken as the tissue becomes infected, small patches of plants turn yellow and die. The central shoot detaches easily, and the blackened base is readily visible. Masses of grey/black mycelium may be seen on the affected stem bases.

Spread- will happen with inadequate N, P and K., drought conditions in compacted and well-worn areas in low mown areas. The fungus can survive the winter in a dormant state. Then infection can be initiated especially if the turf is under stress.

Cultural control- is done by once again proper fertilisation and maintaining a good healthy turfgrass and soil. A wet, moist, or humid turf surface will encourage spread. One mistake can be to mistake the disease for drought and irrigate the problem area, this will just encourage spread also. Again, improve drainage with aeration, alleviate compaction and reduce the amount of thatch. Raise mowing heights and avoid plant growth regulators because of the slow growing thy encourage.

Chemical control- Preventative is best for Anthracnose, because unlike Fusarium, once in the turf it will create considerable damage without recovery. This is more effective than curative and if left to eradication stage it will be too late. Watch for outbreaks reports and spray 14 to 28 days after initial application if weather conditions have remained conducive. Again, contact your supplier for an available fungicide on the market.

Early stages of Anthracnose Ref. Turfhacker.ocm
Advanced stages of Anthracnose Ref. Nuturf.com

Red Thread (Corticium Fuciformis)

Again, a fungus found in cool, temperate, and humid areas of the world. Prevalent during Spring and Autumn on slow growing nitrogen deficient turfgrass. Mostly found in Fescue grass species but not confined to these.

Symptoms- depends on the grass species and severity of the attack. Will start in small 5-50cm diameter patches of dead leaves interspersed with living plants giving a scorched appearance. The patch becomes water soaked and die quickly. Tan colour of dead leaves maybe the first signs. Closer inspection will reveal pale pink to red needle like outgrowth, these red strands are part of the fungus.

Spread- it can survive unfavourable conditions on infected leaves or in thatch. Can also survive temperatures from -20 degrees up to 32 degrees and can remain visible for two years when dry. It is spread by running water, equipment, people, animals and can also be spread by wind. Heavy dews, drizzle and fog all favour the disease when the temperature is correct 18-24 degrees. Prolonged periods of wetness also a factor. It mostly affects fescues but does not really affect the playing quality of the surface but does reduce the aesthetic appearance. Rye grass is also very susceptible. 

Cultural control- low fertility and especially Nitrogen deficiency along with warm and wet conditions in a slow growing turf are the primary problems. So, a balanced nutritional programme with balanced Nitrogen inputs along with the usual improving the drainage through aeration will solve the problem.

Chemical control- use recommended rates of nitrogen, overseed with grass varieties that are less susceptible if possible. Again, be careful of plant growth regulators to make sure growth does not slow. If nitrogen input does not supress disease apply a suitable fungicide recommended by your supplier.

`Red Thread Ref. Greencast.com

A quick note on two other possible diseases that could be found: –

Take-All Patch (Gaeumannomyces Graminis)

This is predominately found in USGA spec sand based green. This disease attacks the roots and stolon’s in Bentgrass. It will be a slight reddening or bronzing of the bentgrass usually in the summer months. In a stressed turf it may appear red/brown before dying and turning a dull brown colour. Symptoms may fade in Autumn and winter. The roots and crown are infected and become dark brown to black. Meadow/poa annua is sometimes affected. Can come after 3-4 years in a new green and be gone by 6-7 year. As usual, more likely to spread in a damp turfgrass with an inadequate nutritional programme. Fungicide can be used.

Advanced stage of Take-All patch. Ref. Greencast.com
Fairy-Rings (Basidiomycetes)

Is a mushroom fungus. There are three different types. The sign and symptoms will be clear, typically appear as rings of dark green and fast-growing turf. May also appear as rings of slow growing or killed turf. Rings will generally have a width of 5-30cm and form a continuous ring from 1-70m across. They are produced by fungi that live in thatch and soil.

  • Type 1- brown rings of dead turf
  • Type 2- green rings of stimulated turf growth
  • Type 3- presence of mushrooms or puffballs.

Usually cultural operations aeration, topdressing etc, then depending on which type contact your supplier as regards a fungicide to apply if necessary.

Type 1: Dead Turf Ref: Greencast,com
Type 2: Stimulated Growth
Type 3: Mushroom


There are three active ingredients available for insecticides at the moment, Chlorpyrifos, Imidacloprid and Pyrethrins.

Earthworms (Lumbricus Terrestris)

These are the most important ones. They range from millimetres to much larger and are important for ensuring soil movement and efficient nutrient cycling. Their activity aerates and mixes the soil and is important for mineralisation and nutrient uptake by plants. They are good for soil structure because they create a multitude of channels which allow aeration and drainage. They do more of this at night. In many soils they play a major role in converting large amounts of organic matter into rich humus.

Chemically speaking there are benefits of having worms, they can ingest soil particles and stones up to 1.25mm big. When the worm excretes the minerals and plants nutrients are made available in an assessable form.

Control-of worms is getting harder to do chemically because of banned substances. Carbendazim and Thiophanate Methyl were used but not now. Caste Clear is used and is based on ammonium nitrate and sulphur. Keeping pH down, controlling thatch and o/m will reduce the food supply for earthworms. If small amounts of worm cast are your problem, I would not worry too much, if birds are tearing your greens apart trying to get the worms then look to your supplier for an appropriate chemical solution.

Typical Earthworm and worm cast.

Leatherjackets are the larval of the Crane-Fly (Daddy Long Legs). Their life cycle starts when the adult crane-fly lays its eggs usually in August/September. They then hatch in October and a small grub appears after 21 days. The grub will then make its way deeper underground to get food which will be roots, stems and crown. The 4th stage is after they have fed themselves for the winter, they begin to surface in late Spring early Summer to then change into the adult crane-fly.

If soil temperatures drop, they will then go deeper into the soil and then back up when temperatures rise. At the final stage they are called a Pupae.

Because they are a re-occuring pest, control should be done just after hatching or early in the life cycle. microclimate is vital for them as they will look for shelter, shaded and moisture areas.

Control- Nemasys J is a biological used to control them. This is a parasitic nematode which kills the leatherjackets but is harmless to wildlife. This should be applied to the turf when the temperature is over 10 degrees. To check for leatherjackets, do a soil sample using lemon scented washing-up liquid. This will help monitor if grubs go over 25-30 larvae per square meter indicates a problem. Nemasys J works by invading the pest from the inside out. After several weeks they will have shrunk, and their body’s starts to turn black. Birds will start to leave them alone now as they are not an attractive food source. At this stage, the leatherjackets will have been totally destroyed.


Chafer Grubs

The Chafer Grub is the larvae of the Chafer Beetle. The most frequently found grub is the garden grub. They have white bodies and brown heads and are curved. They grow to about 1.2cm long. Their life cycle starts with the chafer beetle laying eggs in July. They then hatch after about 5 weeks and the emerging grubs feed on grass roots until late Autumn. They then burrow deeper and hibernate for winter. The grubs then pupate and in Spring the new adults dig their way out of the soil.

The damage seen to the turf is seen as patches patches of dead or dying grass, similar to leatherjackets. Grass will be easily pulled up with little or no growth.

Control- Biological control is done with Nemasys G. This contains a nematode which kills the chafer grub bit is harmless to wildlife. Soil temperature is important and must be above 12 degrees. Simply mix the nematode powder with water and apply. When larvae are present the turf should be watered so that the turf does not suffer drought as a result of a weaker root system. Merit turf is a chemical also used for control.

Chafer Grubs
Fever Fly

These flies eat the roots close to the surface. They lay their eggs in April/May below the surface. They then hatch into small brown legless larvae which feeds in August. They are rare but difficult to control. Control can be done with sulphate iron and detergents are used to antagonise the larvae as it brings them to the surface.


In May adults appear and their eggs on grass stems and larvae burrow inside the stems and feed. Can be a severe problem on newly sown grass. They will leave a white grub in the stem which will wither and die. The main chemical is Crossfire (Chloropyrifos).

Birds, Rabbits, Deer, Badgers, Foxes etc

They either damage turf looking for food or damage can be burrowing, grazing, compression, urine, or droppings. Control of this can be done by using fencing, traps, guards, and chemical deterrents. I would not know a lot about this topic, but I would recommend contact your chemical supplier.


There are thousands of weeds in horticulture. Too many to write about. I will give a brief description on them and then show photos of the most common I have seen on pitch and putt courses.

The main cause of weed infestation on our courses is from damaged or stressed turf being invaded. We have seen by now the way we can damage and stress turfgrass, wear and tear, poor nutrition management. One of the biggest culprits is scalping. We might scalp a green or collar and think “ah it will grow back”. Sometimes it does, but we have given a weed a chance to invade. For us, a weed on a green or collar is mortal sin, that can be and should be avoided. Not all weeds have to be sprayed for, if you see weed on a green cut it out and repair the hole like repairing a pitch mark. The bigger the leaf grows the more grass coverage you are losing.

Control- Selective herbicides supress or kill weeds without damaging the turfgrass. This done because of the difference between physiological and biochemical make-up for weeds and grasses. It is done by translocated selectives and must be sprayed when turfgrass is actively growing. MCPA, Dicamba, Verdone and 2.4-D are some of the active ingredients used depending on the weed. Bags of fertiliser can be purchased that contain Herbicides.

There are companies that can blanket spray your course using a tractor mounted sprayer. They are reasonably priced so ask the DCB for further details.  

The following are some of the weeds found on pitch and putt courses:

Cats Ear