Pests and Diseases of Turf Tuesday 4 th

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

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 2

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 3

Leatherjacket (Tipula Paludosa) • Leatherjackets are 20 -40 mm 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-strawbrown 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 4 th May 2010 RHS Level 2 Certificate in Horticulture 4

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 5

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

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 7

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

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 (5568ºC). • 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 4 th May 2010 RHS Level 2 Certificate in Horticulture 9

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 10

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 11

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

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

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 14

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 seedbed for germinating weeds Tuesday 4 th May 2010 • Casts produce an uneven playing surface • May produce a squelchy, slow drying sword • The presence of worms may encourage mole activity RHS Level 2 Certificate in Horticulture 15

Control of Earthworms • Earthworm activity can be reduced by appropriate cultural methods by • Reducing soil p. H 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 4 th May 2010 RHS Level 2 Certificate in Horticulture 16

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

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 18

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 19

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

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 Tuesday 4 th May 2010 • Box off clippings • Avoid excessive nitrogen fertilisers especially in autumn • Avoid the use of lime • Use resistant grass cultivars RHS Level 2 Certificate in Horticulture 21

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 Tuesday 4 th May 2010 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. RHS Level 2 Certificate in Horticulture 22

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

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 24

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

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. Tuesday 4 th May 2010 • 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 RHS Level 2 Certificate in Horticulture 26

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 4 th May 2010 RHS Level 2 Certificate in Horticulture 27

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

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 -10 cm high may develop Tuesday 4 th May 2010 RHS Level 2 Certificate in Horticulture 29

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 30 cm and extending 30 cm beyond the edges of the ring. • Fill in with new topsoil and re-seed. Tuesday 4 th May 2010 RHS Level 2 Certificate in Horticulture 30

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

Sources of Information • Rolawn http: //www. rolawndirect. co. uk/. / • Bayer Garden http: //www. bayergarden. co. uk/ • The Maintenance Procedures of Turf http: //www. onlineturf. co. uk/static/Chapter 3. pdf • Hessayon, D. G. (1997) The Lawn Expert. pbi Publications, Waltham cross. Tuesday 4 th May 2010 RHS Level 2 Certificate in Horticulture 32