Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 1 Pests and Diseases of Turf

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 2 Pests The few animal pests that cause damage to turf can be categorised according to the nature of the damage. Pests either eat live plant tissue or Pests that mix or disturb the soil or turf surface.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 3 Tissue Eating Pests In the main these are species of insects of which the two most common and damaging are the –Leather jacket and the –Chafer grub Letherjackets are the larval form of the Daddy-Long-Legs. or Crane fly. Chafer grub are the larva of the Chafer Beetle

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 4 Leatherjacket (Tipula Paludosa) Leatherjackets are 20-40mm long brown or greyish grubs that occur in the surface of the turf. The damage they cause by eating plant roots is usually first observed by patches of pale-straw- brown grass. The grass subsequently dies leaving bare parches. Symptoms are most obvious and severe in dry sunny weather Leatherjackets are common on large open areas of undisturbed grassland. Leatherjackets prefer heaver soils

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 5 Leatherjacket Larva and the Adult (Tipula Paludosa) After heavy rain or having thoroughly watered any yellow patches in the lawn, cover them with black plastic sacks and leave overnight. The leatherjackets will come to the surface and can be collected in the morning

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 6 Leatherjacket Control Use the biological control Steinernema feltiae, which should be applied while the ground is still moist and warm in late-autumn. Treat the lawn with an insecticide containing imidacloprid from May to October.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 7 Chafer grubs (Phyllopertha Horticola) Chafer grubs have fat pale waxy bodies with a characteristic brown head. They may be up to 1 ½ inches in length and are always “comma” shaped. Damage is similar to that of the leather jacket, although they prefer lighter soils.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 8 Chafer Grub Larva and the Adult Click Beetle (Phyllopertha Horticola)

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 9 Chafer Grub Larva Control You can buy pathogenic nematodes, Heterorhabditis megidis, which attack the larvae by infecting them with a fatal bacterial disease. These can be watered into the soil during the summer to early autumn when the ground is moist and soil temperature range between 12-20ºC (55- 68ºC). A pesticide - Provado Lawn Grub Killer - is available to home gardeners for controlling chafer grubs in lawns. The product contains imidacloprid. The best time for treatment is in June to July, when the more vulnerable young larvae are present.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 10 Cutworms (Noctua pronuba) Other pests in this category are cutworms however these rarely need control. Cutworms are the larvae (caterpillars) of several species of night-flying moths. There are no approved insecticides currently available to amateur gardeners to control cutworms.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 11 Wireworms (Agriotes species ) Other pests in this category are wireworms however these rarely need control. Wireworms are the larvae of the click beetle. There are no effective chemicals available for wireworm control

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 12 Cutworms (Noctua pronuba)

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 13 Wireworm (Agriotes species)

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 14 Soil and Turf Disturbing Pests As a pest the most serious one is the earthworm. Occasionally birds such as rooks and starlings may cause damage to the surface in their search for grubs and worms. Other pests in this category are mammals such as moles, rabbits, dogs, foxes and deer.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 15 Problems of Worms in Turf Casts may smoother turf grasses Casts are unsightly Casts smear on the playing surface Casts may contain small stones which may damage mowers Casts provide an ideal seed seedbed for germinating weeds Casts produce an uneven playing surface May produce a squelchy, slow drying sword The presence of worms may encourage mole activity

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 16 Control of Earthworms Earthworm activity can be reduced by appropriate cultural methods by Reducing soil pH and Organic matter content Worms do not like acidic conditions and feed off organic matter. Use acidic fertilisers and implement regular scarification and aeration to remove thatch and organic matter

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 17 Diseases of Turf Grass

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 18 Diseases of Turf Grass In horticulture generally, fungal, bacterial and viral agents may cause plant disease, however, in turf fungi cause the vast majority of disease. Not all fungi however associated with turf and soil are harmful. Many are beneficial as they decompose plant material e.g. thatch and organic matter in turn releasing nutrients.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 19 Factors Affecting the Growth of Fungi Temperature – fungi do not grow well below about five degrees centigrade but flourish around 20 degrees centigrade Moisture – is necessary for germination of fungal spores. High humidity also encourages the spread of fungi. Light – plants in shade are more prone to disease because of weak growth.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 20 Factors Affecting the Growth of Fungi Wind – air movement removes water from the grass keeping turf dry and less susceptible to disease. Soil pH – can affect fungal growth and development

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 21 Cultural Control of Turf Grass Disease Maintain a vigorous growing sward Moisture control to avoid humid surface conditions, e.g. switching or brushing Ensure free movement of air over turf surface Regular aeration treatments Reduce thatch by scarification/verticutting Box off clippings Avoid excessive nitrogen fertilisers especially in autumn Avoid the use of lime Use resistant grass cultivars

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 22 Chemical Control of Fungal Disease in Turf Systemic Fungicides Used during periods of active growth and are absorbed by the foliage and transolicated throughout the plant Contact Fungicides These chemicals act upon the disease on contact with it These are frequently used during the dormant growth periods but can be used at any time of the year.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 23 Fusarium Patch - Snow mould (Fusarium nivale) This is the commonest fungal disease of lawns. Prevalent in autumn and in spring. In moist weather the edges of the diseased areas may be covered with white or pale pink fluffy mould. The first signs are of small areas yellow grass. Patches increase in size. The grass in the patches is killed.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 24 Fusarium Patch - Snow mould (Fusarium nivale) Avoiding and curing the problem Good lawn care is the secret. Feed your lawn in spring and autumn. Spike the turf and avoid mowing too closely Prevention is better that cure as there are no fungicides available to the amateur

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 25 Fusarium Patch - Snow mould (Fusarium nivale)

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 26 Red Thread (Laetisaria fuciformis) Fine-leaved grasses are susceptible to attack. In late summer or autumn look for irregular patches of bleached grass which later take on a pinkish tinge. In moist weather you will find small red needle like growths standing up from the leaves of grass. Grass is not killed but it is unsightly until the bleached patches recover

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 27 Red Thread (Laetisaria fuciformis) Avoiding and curing the problem Curing the disease is never easy, avoid infection. Do not use a high nitrogen-rich fertiliser in autumn or winter, spike the turf regularly and never walk on the lawn when it is covered with snow.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 28 Red Thread (Laetisaria fuciformis)

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 29 Fairy rings (Marasmius oreades) Rings develop on the turf which increases in size as the fungus spreads. Around the periphery of the ring one or more zones of very lush green grass develop. Between the rings the area is dead and brown. Pale brown slender toadstools 4-10cm high may develop

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 30 Fairy rings (Maramius oreades) Avoiding and curing the problem There is no chemical control available. Rake up and dispose of toadstools, before the caps open and release spores. Mow affected area separately collect and burn mowings. Dig out the ring to a depth of 30cm and extending 30cm beyond the edges of the ring. Fill in with new topsoil and re-seed.

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 31 Fairy rings (Maramius oreades)

Tuesday 4th May 2010RHS Level 2 Certificate in Horticulture 32 Sources of Information Rolawn Bayer Garden The Maintenance Procedures of Turf Hessayon, D. G. (1997) The Lawn Expert. pbi Publications, Waltham cross.