Red thread is one of the most common fungal patch diseases found on lawns, particularly where the turf is deficient in nitrogen. It causes brown patches of turf, especially during a wet summer
What is red thread?
Red thread is a common cause of patches of dead grass on lawns during wet summers and in autumn. It is caused by the fungus Laetisariafuciformis. Red thread will rarely kill the grass completely, and the patches will recover with appropriate remedial action. The disease can develop at any time of year, but is most common in late summer and autumn.
It is most serious on red fescue (Festucarubra), but other fescues, bents (Agrostis spp.), perennial ryegrass (Loliumperenne) and annual meadow grass (Poaannua) are also attacked.
You may see the following symptoms:
- • Patches of affected grass with a reddish tinge at first, later becoming light brown or almost bleached in appearance
- • Patches vary in size from 7.5cm (3in) to 25cm (10in) in diameter but can be much larger
Two types of fungal growth may be seen on the patches, particularly under wet or humid conditions. Both are visible to the naked eye, but are seen better with a hand lens or magnifying glass.
- • The first takes the form of small, pink, cottony flocks, and can be confused with growth of the fungus causing snow mould
- • The second is specific to red thread, and gives the disease its common name. Pinkish-red, gelatinous, thread-like structures (stromata), 1-2mm (less than ¼in) in length, are produced on the leaves and may bind them together
Fusarium patch, commonly called snow mould, is a common cause of brown patches on lawns, particularly in autumn or during mild spells in winter.
What is fusarium patch?
This disease is caused by the fungus Monographellanivalis (formally Fusariumnivale). Unfortunately, it is one of the most damaging diseases of turf grasses and can be difficult to control. It is found most frequently during autumn, winter and early spring, but attacks can occur at any time of the year.
The disease is sometimes very noticeable after thaws of snow, when it is given the common name of snow mould.
Fusarium patch is particularly troublesome on annual meadow grass (Poaannua), but can also affect bents (Agrostis species), fescues (Festucaspecies) and perennial rye-grass (Loliumperenne).
What to look out for;
- • The disease is first noticed as small patches of yellowish, dying grass that later turn brown
- • Patches increase in size and may reach 30cm (12in) or more in diameter, often merging together so that large areas can be affected
- • During wet conditions a white or pinkish, cottony fungal growth may be noticed, particularly at the margins of the patch. This is not to be confused with slime moulds in turf
Leatherjackets can be damaging lawn pests and also sometimes kill small plants in flower beds and vegetable plots by eating the roots and stem bases. They are often more numerous after a wet autumn, as damp conditions favour survival of the eggs and young larvae.
What are leatherjackets?
Leatherjackets are the soil-dwelling larvae of flies known as crane flies or daddy-longlegs.
How to tell if leatherjackets are a problem in your garden;
- • Lawns develop patches where the grasses turn yellowish brown and die. This can be distinguished from similar effects caused by lawn diseases or adverse growing conditions by lifting the affected turf and finding leatherjackets in the surface layers of the soil
- • Crows, magpies, rooks and starlings will search for leatherjackets in turf. These birds leave small round holes in the turf where they have inserted their beaks
- • Leatherjackets have elongate tubular bodies, up to 30mm long, and are greyish brown. They have no legs or obvious head
- • In flower beds or vegetable plots, seedlings and small plants are killed when the stems are damaged at soil level
A combination of chafer grubs and the larger animals that feed on them can quickly turn a neat lawn into something that resembles a ploughed field.
What are chafer grubs?
Chafer grubs are soil-dwelling larvae of chafer beetles. They feed on plant roots.
Chafer grubs eat the roots of grasses and other plants. Evidence of their activities can be seen in a number of ways;
- Damage to lawns is most obvious between autumn and spring when the grubs are reaching maturity
- Patches of the lawn may become yellowish
- Birds, particularly of the crow family (eg jays, magpies, rooks and crows), and badgers and foxes feed on the grubs, tearing up the loosened turf in the process
- Damaging infestations can be highly localised and sporadic in occurrence
- Chafer grubs can be found in the soil under the loose turf. They have stout white bodies curved in a C shape, light brown heads, with three pairs of legs at the head end. They are bigger than the adult beetles and, if straightened out, would be up to 18mm (almost 3/4in) long
- Other less troublesome species of chafer grubs can also occur in turf and these can have larvae up to 30mm (over an inch)
- Similar damage in lawns can also be caused by leatherjackets
Cause: Over time the soil that the lawn grows on can become compacted due to a number of reasons such as use for sports, walking, vehicles, parking and children playing. This soil compaction can have a negative effect on your lawn. The damage to your lawn from soil compaction results from the pore spaces within the soil becoming smaller and this leads to both a reduced amount of air held in the soil, restricted air flow and reduced water infiltration into the soil. These results of soil compaction are damaging to a lawns health.
Reduced air levels and restricted air circulation in the soil means that the grass roots are less able to take up oxygen. Reduced soil pore space also leads reduced levels of nutrient uptake from the soil. Oxygen is a vital input into a plants growth cycle. If the ability of water to infiltrate the soil is limited by soil compaction then the water will not infiltrate as deeply into the soil as normal, this means the lawns roots will not develop as deeply and so the lawn will be more at risk from drought and other environmental stresses. Soil compaction also means there is greater resistance against the roots as they try to develop to greater depths. Poor development of roots below the soil will result in a poor lawn condition above the soil.
Solution: Hollow-tine Aeration: is the process of removing thousands of cores from your lawn to help alleviate the above problem
If your lawn contains a considerable buildup of thatch then we can use hollow-tine aeration to help break down the thatch. This process occurs as the cores of soil that are left on the lawn surface by Hollow-tine aeration introduce soil micro-organisms into the thatch layer. These micro-organisms breakdown the layer of thatch and return nutrients to the soil.
Cause: Poor growing conditions favour the growth of moss in lawns. These might include:
- • Sparse grass cover
- • Worn areas of turf, especially along walkways and where children play
- • Shady areas, especially beneath trees
- • Compacted soil
- • Wet weather and waterlogged conditions
- • Drought-stressed grass
- • Mowing too close
- • Impoverished lawns or infertile soil
- • Poorly prepared or poorly maintained lawns
- • Acidic soil conditions
- • Surface thatch
Solution: The first thing to do is to assess the causes of the moss issue to provide a long term solution to keeping the moss to a minimum. This can be quite difficult given the changeable climate here in the UK. Scarification is good place to start. This is the process by which the moss and surface thatch which moss can grow on is removed. This allows air and water to get down to the root zone whilst slicing the grass plant vertically thus promoting new growth. Scarification combined with Hollow-tine aeration is a perfect way to ensure your lawn has a great start to the upcoming growing season.