Public Planting Establishment (Pests & Diseases of Public Spaces)

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Public Planting Establishment (Pests & Diseases of Public Spaces)

  1. 1. 1. Introduction The purpose of this project is to investigate, describe, and define plant pests, diseases and disorders, vandalism in context with open public spaces and the historic and contemporary methods of identification, prevention, mitigation and control. Without a thorough understanding of the susceptibility of planting schemes to pest, disease, disorders and vandalism and how to manage/prevent them, poor design will be inevitable. Planners, developers, local authorities, etc, are looking towards environmental (sustainable) design for efficient, cost effective schemes. Environmental design is “the philosophy of designing physical objects, the built environment and services to comply with the principles of the economic, social and ecological sustainability” (McLennan, 2004). This report will look to answer many questions, among them: • What are plant pests/diseases/disorders? • What is vandalism? • What are their effects on public spaces? • What are their causes? • How are they identified? • What are their past/present/future controls & how are they prevented? The method to answering these questions will be through studying and analyzing a part of the existing material on the subject, in regards to landscape architecture. The report will then contextualize this information and form conclusions and recommendations based on this information. This report will be relevant and useful in terms of landscape architecture and the preparation of a planting scheme resistant to pests, diseases, disorders and vandalism after a site analysis. 2. Causes & Effects 2.1 Plant Pests Plant pests are animals that cause damage to cultivated, ornamental and vegetable, plants (Bell, 2002). They are most active and damaging in mono-cultural environments. Most pests, as in the case of invertebrates, are seasonal and their life cycle is closely related to, and utterly dependent on plants. The largest group in the category of plant pests is Insects (Invertebrates). Damage caused by plants pest includes; sap sucking, disease transmission, defoliation, leaf, stem and root mining/tunnelling. A plants immune system may react badly to attack from a pest leading to the formation of blisters. Infection from diseases is also made easier by initial attacks of pests (Brickell, 2002). It is important to control plant pests as many are vectors for viruses and diseases, carrying them from plant to plant. Others meanwhile, cause tissue damage to planting, 1
  2. 2. allowing diseases to enter the plant(s) through the wound (Secondary Infection). Plant pests can be divided into the following groups: Arthropods, Molluscs, Nematodes & Vertebrates. 2.1.1 Animal Pests Animal pests include Deer, Dogs, Cats, Birds & Squirrels to name but a few. They are larger than invertebrate pests and so can cause much damage on their own. The biggest complaint of animal pests is bark damage. This is the source of much tree/plant damage, due to secondary infection from disease (Bell, 2002). Damage done to plants is usually superficial, with new buds & shoots eaten and shrubs dug up or trampled upon. Animal pests are controlled and prevented by repellent sprays, fences and mechanical scarers. In the case of rats and mice, poisons are used in conjunction with traps. The path to avoiding problems with animal pests is to design areas unattractive to them. This is done by removing possible sites for nesting and shelter and using plants which do not appeal to their taste buds. Fencing can also be used to prevent access or to shield plants from damage. Decoy plants can also be used to divert attention away from plants susceptible to damage (Brickell, 2002). 2.1.2 Invertebrate Pests There is nearly 20 million species of insects on this planet. An estimated 50% of this plant material feed on living plants. Some species attack a wide range of plant species and others need a specific plant to thrive (Bell, 2002). The result is massive losses and costs in terms of maintenance & repair of public planting spaces. These facts stress the importance of an integrated pest management system, through chemical, biological or other means. Plants are important to invertebrate pests in terms of food, shelter and reproduction. Invertebrates are problematic, not only in terms of the damage they do, but also the viruses and other diseases that they are vectors for (Brickell, 2002). Through understanding of invertebrate pests, they can be destroyed upon discovery or repelled completely by selective planting. By designing planting schemes effectively, the landscape architect should be able to interrupt the life cycle of invertebrates, increase the number of their natural predators and overall produce a planting scheme that is resistant to invertebrate pest damage (Bird, 2004). Woolly Aphid (Fig. 1) 2.2 Plant Diseases & Disorders 2
  3. 3. Plant Diseases are caused by viruses, bacteria and fungi. Many are classified as Secondary infections. This means that they infected the plant due to the action of another living organism, i.e. entry through a bark wound caused by Deer (Bell, 2002). They spread easily with the aid of wind & mechanical vectors. The amount of damage done to a plant by a disease is dependent upon a number of factors, such as weather, growing conditions, pre- existing health of plant & other present aliments (Brickell, 2002). By understanding how diseases, and disorders are caused, the landscape architect will be able to prevent and/or mitigate their effects. Disease spread by wind can be stopped/hindered by a barrier of disease resistant trees, sheltering a susceptible area of planting. Poly-cultures (i.e. mixed plantings) can also be used to produce disease/disorder resistant planting schemes (Bird, 2004). The right design, with the right choice of plants can help offset the effects of pollution on planting, i.e. using Ferns to absorb heavy metals out of soil and away from other plants. 2.2.1 Fungi A fungus is a plant without Chlorophyll. It obtains nourishment as a parasite through symbiosis. It spreads and grows through mycelium and spores. All infected leaves, even those that fall, should be destroyed to curb the spread of the disease (Bell, 2002). In comparison, fungi diseases are much more common than bacterial infections. Along with several strains of bacteria and viruses, some species of fungi have become resistant to chemical sprays and treatments (Brickell, 2002). 2.2.2 Bacteria Bacteria are single celled organisms. They survive as either saprophytes or parasites. They spread by contaminated soil and tools. They can also be moved by wind, rain, insects and survive on the surface of seed coats, attacking when germination occurs. They infect plants through the stomata or open wounds. This is why it is important to seal all wounds, even after pruning, with Aqua-seal 50 to act as a semi- permeable barrier that stops infection. Bacteria cause abnormal cell growth and eventually cell/plant death. Some bacteria are used in a beneficial way, in terms of biological controls (Bell, 2002). Bacterial Canker (Fig. 2) 2.2.3 Viruses 3
  4. 4. Viruses are sub-microscopic particles which clone themselves to represent their host cell. All viruses are parasites and have no other means of surviving (Bell, 2002). Viruses move from plant to plant by mechanical or vector means. Viruses spread through the host plant means of systemic infection from one plant cell to the other. When the virus enters the phloem cells of the plant, it multiplies rapidly. Plant death doesn’t always, but most certainly, follows this stage. 2.2.4 Physiological Disorders Plant (physiological) disorders are caused by non-infectious agents. They produce disease like symptoms in the affected plant. They have many causes including nutrient deficiency, pollution, water stress and light (Brickell, 2002). Unsatisfactory growing conditions and fluctuating temperatures/water and food supply are the commonest causes. Physiological disorders make plants more susceptible to pest or disease attack (Secondary Infection). It is only in extreme cases that a plant will die solely from a physiological disorder. Nutrient deficiency occurs when the nutrient supply to the plant is inadequate (Tracey, 2007). Nutrients may be still present in the soil, but unavailable to the plant due to extremes in pH, water stress and/or high cation exchange capacity, caused by a high clay content in the soil. Nitrogen Deficiency (Fig. 3) Pollution causes physiological disorders in plants by affecting photosynthesis (pore/leaf blockage) and introducing poisonous substances into the plant supply. Water stress causes disorders in plants by excess/inadequate transpiration and an unstable water supply. Light, can become a cause of disorders in plants (i.e. lack of light leading to etiolation) (Bell, 2002). 2.3 Vandalism 4
  5. 5. Vandalism has been used as a broad term to describe anti-social behaviour, accidental or not, to criminal activity. Furthermore, vandalism can be divided into 4 sub groups: • Inexplicable vandalism • Deliberate vandalism • Incidental vandalism, & • Institutionalized vandalism The term inexplicable vandalism covers rare, destructive occurrences of vandalism. Its causes are numerous, from chance happenings to psychotic behaviour in individuals. It cannot be anticipated, but protection can be provided to potential fragile targets. Mitigation of this form of vandalism is available through judicial proceedings & law enforcement actions. Deliberate vandalism is the damage, destruction or theft of facilities and properties of a specific site/location. The second most common form of vandalism, overall, it causes more damage to facilities & cost more to prevent and repair. Motivation for damage by this type of vandalism is numerous (Christiansen, 1984). It can be used as a medium for financial gain, i.e. Removal of fencing for scrap, stealing and re-selling of expensive hardscape materials. Damage to facilities can also be caused to gain access and use. Deliberate vandalism also covers the area of “graffiti writing” or “street art”. This is done with no malicious intent in mind, but to simply convey a message. However, it is costly to remove and may offend. Incidental vandalism has the highest occurrence over all other forms of vandalism. Fortunately, it is not the most damaging. It is easily preventable and damage caused can be repaired without high costs. Incidental vandalism covers wear and tear of materials over time, littering, damage to plants (picking flowers, shortcuts, carving names into bark, etc) and general disregard for property. Incidental vandalisms cause(s) lies in the social fabric of the local community (Goldstein, 1996). Institutionalized vandalism is “accepted” or expected damage to public spaces. It occurs with public celebrations, events and gatherings in public spaces. With large concentrations of people in public spaces, damage is expected and the accepted course is to simply repair the damage. The only control for this form of vandalism, short of closing the public space, is to demand deposits from those who book or use the space. This leaves responsibility with them (Goldstein, 1996). If damage costs exceed the received deposit, fines can be issued, with a ban from the said public space, until the fine is paid in full. All the previously discussed forms of vandalism have their roots of destruction based in their social environment; however, the extent of damage done is directly influenced by the surrounding physical environment. While improvements in social mentality can be made, they will not alone stop vandalism in public spaces. The same can be said for physical barriers. These can encourage or “incite” vandalism and can even become vandalized themselves (Christiansen, 1984). 2.3.1 Causes 5
  6. 6. The causes of vandalism have their roots in the physical and social environment, both perceived and actual. In this section the causes of vandalism will be looked at under the following headings: • The Social Environment • The Physical Environment • Sense of Ownership (Lack of) & Community Interaction There is rarely one cause of vandalism. The factors above work together, to create an undesirable environment that results in vandalism of public open spaces. The social environment is influenced by the physical environment and vice versa. The presence of anti social behaviour is not the fault of the designer, but creating an environment that doesn’t control it and/or exacerbates the problem is. It is important for a designer to understand the social environment relevant to the surrounding area (Tracey, 2007). Only then can the designer create an effective design that gives the local community a sense of ownership and pride. It also indicates what degree of protection from vandalism is needed. Bad design of a physical environment can make a bad problem worse. Without proper design considerations, unintentional features that exacerbate vandalism will be created. These are called “Crime Features”. They include areas with insufficient lighting, pathways out of sight and areas with low usage/pedestrian traffic. Elements of this bad design can be both real and perceived. People’s perceptions will lead to an area out of sight, with low traffic and low light to being dangerous. Perceived areas of danger will lead to those said areas becoming abandoned and eventually, havens of anti-social behaviour and vandalism. Also poor understanding of design will increase the likely hood of vandalism (Christiansen, 1984). For example, the concept of permeability, which increases pedestrian flow, traffic & access through the use of pathways, intended for positive interactions. This can provide escape pathways for vandals, increasing the problem. Positive community interactions with public open spaces lead to high pedestrian concentrations in small areas and increase public space usage. The sense of getting caught will deter most vandals. Attracting high level of pedestrians to the area can be done by sufficient lighting, fencing, minimal areas hidden from sight etc. However, high levels of pedestrian flow/usage will allow coverage & anonymity of criminals. Involving the community in the public space through the use of design (inclusion of community gardens, etc) will bring greater security to the area. Since vandalism itself is (usually) rooted in the local community, by involving patrons of the public space it brings a sense of ownership (Goldstein, 1996). 3. Controls 6
  7. 7. Pest and disease control methods have been practiced over many centuries. Many were formulated from trial and error. While ineffective on their own, they are usually integrated individually into a larger system of controls mutually supporting each other. Controls can be defined as measures taken to remove or reduce damage/loss below a level of economic value. The following sections will describe various controls and their methods. 3.1 Integrated Pest and Disease Control Integrated control is the best practice in the limitation and management of pest & disease problems. It focuses on prevention, cure and control. Integrated control uses several systems to be effective (Bell, 2002). These can include companion planting, xeriscaping, biological control and permaculture. Integrated control is focused more on prevention, rather than cure. This proves more successful in the long run to plant health and in keeping maintenance costs down. This is done by the selection of strong, resistant, vigorous growing plants (Brickell, 2002). For the landscape architect to implement an integrated control effectively, they must understand the needs and properties of their planting selection(s). This is where the best management practice of integrated control comes into action. This involves: • Analyzing the site properly and identifying plants that would thrive in this environment. • Identifying pests and diseases that would be problematic in this environment • Identifying plant species/cultivars that would be resistant to these pests & diseases • Using design to create optimum growing conditions for selected plants so they have a competitive advantage over pests and disease • Using design to minimize the chances of a physiological disorder occurring within the planting system(s) • Inspection of selected plants: o Before purchase o On delivery to site o After planting on site o At regular intervals after planting on site 3.2 Chemical Controls 7
  8. 8. 3.2.1 Insecticides Insecticides are used to control and eliminate local invertebrate populations. They come in a variety of powders, dust and liquid applications. They are now mostly applied by pressure sprayers. There are 3 types of Insecticides: 1) Insect Contact Mostly used on Aphids and other insects with high populations in close quarters. They are only effective in local populations. The Insecticide will only kill whatever it comes into contact with. It has no residual effect after application. 2) Leaf Contact Leaf contact Insecticides work by coating the leaves of plants. When insect pests, such as caterpillars/aphids eat the treated leaves, they die. They also have an after effect. However, the treatment can be washed off the leaves by rainfall. 3) Systemic The Insecticide is absorbed into the plant and its sap. Systemic insecticides are effective and do not have to come into direct contact with pests. They also have an after effect, which is not washed off by the rain. Complete plant cover is not essential and one application provides enough protection for the growing season. Chemical insecticides are not popular due to their association with pollution, environmental damage and cancer. Also, species of invertebrates pests are becoming immune to the most widely used sprays, making them more problematic and resistant (Brickell, 2002). Furthermore, other beneficial invertebrates are becoming caught in the crossfire and having their numbers reduced (Bird, 2004). Many active ingredients have been banned, leading to no soil pest insecticides and a narrower range of systemic insecticides. Another danger associated with Insecticides is Accumulative Toxicity, i.e. DDT (Bell, 2002). 3.2.2 Fungicides 8
  9. 9. Less widely used than insecticides, Fungicides are used to prevent, control and cure diseases caused by fungi (Brickell, 2002). There are two types: 1) Preventive Preventive fungicides work by coating the leaves and destroying any spores which land on them. To be truly effective, the fungicide must be applied before the first symptoms of the disease. 2) Systemic Systemic fungicides work by moving inside the plant, into its sap. As a preventive, it is much more successful than the preventive fungicide as it gets greater coverage. As with insecticides, the range of chemical fungicides has been narrowed due to environmental damage caused by their extensive use. Organic fertilisers are proven and tested. These include sulphur & copper applications (Bell, 2002). 3.2.3 Phytotoxicity Phytotoxicity occurs in plants liable to severe reactions to insecticidal and fungicidal sprays/powders. Plants most susceptible to phytotoxicity are those with a pre-existing physiological disorder (stress), in flower, young immature plants and others who are sensitive at certain periods during their growing cycle. Also, several plants may become damaged if a group of different plants are being sprayed with the same chemical, with others being more prone to an adverse reaction (Brickell, 2002). Good design can avoid these problems. If chemical (insecticides, fungicides, etc) are to be used in a planting scheme, proper management to avoid complication must be implemented. Monocultures can be effective, as there is no risk of a reaction to the chemical from other plants. Or, design can be used to remove the risk of phytotoxicity altogether, by making the use of chemical control redundant. Several methods to do this will be discussed in the following sections. 3.3 Organic Controls 3.3.1 Companion Planting Companion planting is a gardening/landscaping technique that carefully chooses and grows compatible plants with one another for their mutual benefit. It origins lay in European cottage gardens from the Middle Ages (Bird, 2004). Companion planting is quite a desirable practice as a mixture of species of plants that have different tolerances to disease, bacteria and pests will lessen damage done to a planting scheme (Lamb, 2008). This approach to planting also advocates the use of “green manures”, plants that draw nutrients from deeper soil and make them available to other plants when they are tilled back into the soil. This solves any troublesome 9
  10. 10. encounters with nitrogen deficiencies. This practice is also repeated with leguminous plants that fix nitrogen from the air (Tracey, 2007). Companion planting is also planned to cover ground throughout the year. This stops or impedes the colonization of algae, moss and the invasion of weeds. The arrangement of planting is paramount to the success of companion planting. Different plant groups are planted together to repel pests, resist disease and prevent nutrient deficiencies in the soil. This practice focuses on mixed cultures rather than monocultures (Brickell, 2002). Monocultures tend to be more prone to disease and pest damage. Concentrations of mono-cultural planting allows for the rapid spread and reproduction of pests and diseases (Lamb, 2008). In most cases, chemical controls must be used to ensure the success of a monoculture. In terms of pests, mixed cultures control their numbers by attracting the problem pest’s natural predators into the vicinity (Bird, 2004). For example, an area dedicated simply to roses would be a haven for greenfly, with the problem likely to spiral out of control as roses do not attract ladybugs or lacewings, aphid’s natural predator (control). Also planting can be used to repel pest away from the planting scheme by using plants such as Marigolds, Lavenders and Basil. Other plants can be used to attract pest away from other plants (Decoy Plants), i.e. Sunflower. Disease resistance is another cornerstone of companion planting. Champions of companion planting tend to favour older stocks of plants as modern plant breeding has eliminated certain genes and immunities from new plant cultivars. 3.3.2 Biological Control Biological control is the direct or indirect use of living organisms to reduce the number of damaging pests below a level of economic importance (Brickell, 2002). Biological control describes the process of limiting damage done by pests with the purposeful introduction of natural predators, parasites and diseases harmful to them. Biological control is a naturally occurring force that is replicated and implemented to remove the need for chemical insecticides (Bell, 2002). It is mostly used to deter and control pests through predatory means. However, biological control practices are also set up to stop fungi and disease becoming a problem. Biological control is an attractive option to pest management. It has few negative factors associated with it, unlike chemical controls and unlike chemical controls, once established it has no additional costs and is relatively permanent (Bird, 2004). In terms of predatory pest control, predators will either hunt and consume their prey or develop a parasitic relationship with the pest. Biological control is designed to use living organism that have no negative effects on non-target/beneficial species. However, it is establishment of Biological controls that is the problem that has plagued growers & researchers. It is a simple fact that predators are driven by instinct and, once unleashed, may eat beneficial insects instead of pests. Transport of biological controls is another problem, as many predatory species die from being incorrectly handled and underfeeding. Another drawback to implementing such a programme is timing. Many pests do most of their damage to young plants in early spring, when very few predators are active (Bell, 2002). Living organisms used in 10
  11. 11. biological control require many optimum conditions to be present for the practice to be successful, such as temperature, humidity, pest numbers and time of year/stage of growth. 3.3.3 Xeriscaping Xeriscaping is a landscaping philosophy that uses as many native, drought resistant plants as possible and arranges them in an efficient design that conserves water (Fuller, 2008). It was first developed by the Denver city authority to combat the deadly droughts that faced the city during the 1970’s. Xeriscaping can reduce irrigation use by 60%. Native planting is used because it is adjusted to the climate. Drought tolerant planting is used on the outskirts of the design, or the furthest points from the water source. Xeriscaping is effective at managing diseases and fungi. This is because it uses a lot less water, which is vital for the colonization, reproduction and spread of diseases and fungi. Without adequate moisture, diseases cannot capitalise. With plants covering the ground and appropriate mulch, no weeds (which may be susceptible to diseases) can colonise. The important part with xeriscaping is to ensure free draining soil and to avoid any areas of pooling water. Appropriate mulches can also be used, ideally inorganic, as organic mulches (bark) can rot, if wet for prolonged periods, giving diseases an environment to thrive in. However care must be taken with inorganic mulches as they absorb heat from the sun, increasing transpiration from plants and soil (Fuller, 2008). Xeriscaping controls Disease by removing one of its necessary needs, water. However, in a climate such as Irelands, Xeriscaping would most likely fail as a planting practice. 3.3.4 Permaculture Peramculture, otherwise known as “Permanent Culture” or Permanent Agriculture”, is the intentional design & maintenance of agriculturally productive ecosystems that have the diversity, stability & sustainability of natural ecosystems, according to permaculture.org. Permaculture is based on philosophies of working with nature, instead of against it. Peramculture incorporates biological controls, mimicking natural relationships, companion planting and nutrient recycling (Lamb, 2008). It is also known as “Restoration Ecology”. The following are the principles of permacultural design: 1. Zones: Areas requiring high maintenance/traffic are placed closer to the centre/access pathways. This minimizes energy and time wasted by transport. 2. Sectors: This principle works in conjunction with the zoning principle. It is a method of further dividing areas of priority within zones. 11
  12. 12. 3. Relative Location: This involves the placement of activities/amenities beside complementary areas within the same zone or adjacent sectors. This maximises energy output from a single area. 4. Single Elements With Multiple Functions: Structures, plants and other elements are placed and designed to meet and supply multiple needs. This maximises their energy output for the amount of space they take up. 5. Single Functions With Multiple Elements: This principle involves the use of multiple elements to replace a single element if it fails. It is often used as a fail-safe approach. 6. Energy Efficiency: This principle dictates that sites must have as little external energy input as possible. This means sites shouldn’t need additional fertilisers, chemical sprays, heavy maintenance etc. 7. Biological Resources: This involves the use of natural relationships to control weeds, pests and disease. Examples include biological control, companion planting and xeriscaping. 8. Plant Succession: Planting schemes develop and evolve over time. By designing an area effectively, plant communities should support each other as they grow through various stages, i.e. Natural Herbaceous Plant Selection otherwise known as Sustainable Plant Communities. 9. Nutrient Recycling: When plants die, they can be composted or tilled back into the soil and used as a natural fertiliser. This not only mimics nature, but also improves energy efficiency with little wastage. 10. Diversity: Peramculture focuses on polycultures instead of monocultures. This stops entire crops from being wiped out by one pest/disease and increases a crops resistance. It also has the positive side effect of increasing bio-diversity. By making areas/amenities, that will inevitably need maintenance, easily accessible, you cut down on energy and time used, hence saving money. By placing zones of less frequent activity in well lit areas you can even reduce vandalism (Lamb, 2008). By using nitrogen fixing plants, green manure, self-seeders & soil binders you can reduce the need for input of external energies (Bird, 2004). 3.4 Vandalism Controls This section, discussing controls or preventative methods of vandalism in public spaces, will be divided into two sections: • Social media, & • Physical media 3.4.1 Social Media 12
  13. 13. Social media is a term which describes the tools used to reduce forms of vandalism, whose main cause(s) lie within social structures/environment. These forms of vandalism include incidental & institutionalized vandalism. The practices of social media used to curb vandalism in public spaces are: Public relation, education, rule enforcement and co-operation (Goldstein, 1996). This form of vandalism control is post-design and in the most part does not concern the landscape architect as it is the local authorities that will dictate action.  Public relations or publicity campaigns  Education of staff & users of public spaces  Rule enforcement  Co-operation with the local community Planning and integration of all these strategies is important for them to work, for as standalone practices they are ineffective. It must be insured that the park is heavily used. Nothing repels vandalism more than a crowded area. Areas with low concentrations of use are perfect for vandalism, as there is less fear of getting caught, the biggest deterrent. 3.4.2 Physical Media While social deterrents to vandalism are mainly down to management after the design stage, physical barriers are the domain of the landscape architect. However, the designer must understand the social causes of vandalism & the habits of the everyday vandal. The physical environment can also, unintentionally, install “crime features”; factors that encourage anti-social behaviour (Goldstein, 1996). By making it physically impossible for vandals to cause damage to their target, one of two actions will be enacted: 1. The vandal will be unable to damage the target with their usual means and give up 2. The vandal will be “incited” to become extreme in their methods and succeed in damaging the target However, proper protection of facilities and amenities will deter most vandals. Remember, most vandalism is impulsive, if the target is harder to destroy/vandalize, it will take longer. This will increase the chances that the vandal will be caught by security. The thought of this in itself acts as a deterrent in the vandals mind (Tracey, 2007). 13
  14. 14. (Fig. 4) Repair of damage facilities & amenities should also be easy, i.e. the replacing of cracked slabs, broken trees, etc. Also, unsightly & offensive graffiti should be easy to remove. This is where choice of materials is important to the designer. Access to these facilities should be adequate for maintenance crews. The task of maintenance itself should not disrupt the normal activities of the park (Christiansen, 1984). This is where good design comes into practice. Durable materials should be chosen for easy targets of vandals. The initial start-up costs are easily dwarfed over time by the maintenance/repair bill associated with cheaper/weaker materials. Stronger materials also deter impulsive vandals looking for an easy target to destroy. The landscape architect must choose materials that are durable, easily repaired and still aesthetically pleasing. By making targets hard to destroy or by placing susceptible targets in hard to reach places, vandals are discouraged from destroying them. While vandalism cannot be completely wiped out in public spaces, its damaged can be reduced greatly. The tried and tested approaches of; fences, railings, walls work, but at the cost of aesthetics. It is up to the designer to understand when and how to use them. These structures can become overbearing and give a sense of imprisonment, or in the case of CCTV a loss of privacy (Goldstein, 1996). Innovative ways to curb and deter vandalism can become part of the design, because at the end of the day, the need for fences, railings & walls is due to bad design. 4. Summary There are many problems which affect the success of a design after its implementation, as previously described. They have various causes, but these are stem from lack of understanding and little, if no preventative methods. Pests and diseases have plagued public spaces since their inception. Many controls were perfected through trial and error or by simply replicating nature (permaculture/biological control). Prevention is often better than cure in the case of diseases, as they can spread and destroy planting systems. Vandalism has been present in public spaces just as long as pests and diseases. Its roots lie in the local social environment and it is exacerbated by poor design (“crime features”) (Goldstein, 1996). Integrated Pest and Disease Control is the term given to a series of systems mutually supporting each other. Polycultures are one of the most important features of a IPM (Integrated Pest Management) scheme. Polycultures have a greater resistance to pests and 14
  15. 15. disease, increase biodiversity and form mutually beneficial relationships (nitrogen fixing, repel insects) (Bird, 2004). Controls exist in many forms, yet some are more controversial than others (chemival vs. organic). Prevention and mitigation is only successful by understanding the problem and environment and then implementing a system of integrated control. Very rarely will one control work by itself (Brickell, 2002). Without knowledge of these controls & their correct usage, public spaces will fall into disrepair. The need, attraction and aim of controls are lowering waste, in terms of money and labour. With restriction on funds, due to the current economic climate, the use of labour as a control has fallen into disfavour with authorities. This has led to an increase in the practice of organic controls & sustainable plant communities. In terms of vandalism, the inclusion of community gardens has been used to give a sense of ownership in the local area (Vancouver community gardens, Liz Christy Remembrance gardens New York). Also, better understanding of layouts has been used to remove crime features (Christiansen, 1984). Public spaces are for people. Spaces left to the ravages of vandalism and pests and disease, develop an uninviting appearance. Left unchecked, these problems can reduce or remove the effectiveness of design. Integrated control management is part of good design. 5. Future Pests, diseases, disorders and vandalism increase maintenance costs and degrade the image of a public space. With the current economic climate, a client’s focus will be on keeping costs low. Preventive, long term measures will become the epicentre of any pest, disease and vandalism protection scheme (Bell, 2002). With greater research being developed into wall coatings to prevent vandalism, damage to walls may soon be a thing of the past. Problems will arise in the near future in regards to pests & disease. With cases of resistance to chemicals increasing with fungi and insects, natural controls and preventative measures will be focused on more intensely (Bird, 2004). The use of chemicals should be a last resort and a sign of bad planning and design. Plants resistant to physiological disorders (described as “power plants”) will be used to a greater degree in urban areas as pollution increases, along with fluctuations in (clean) water supplies. In terms of pest and disease resistance, a narrowing genetic range of ornamental planting presents a problem. With new breeds of plants flooding the commercial market and less use of old plant breeds stocks, ornamental plants present themselves as being more susceptible to pests and diseases (Brickell, 2002). New technology, methods and research are now tackling vandalism. In Holland, green walls are being used to cover and block walls susceptible to graffiti/vandalism. It has also been theorized that greenery in urban spaces reduces criminal activity, including vandalism. Water borne coatings are also being used to stop spray paints from penetrating the surfaces of walls/structures. This allows the graffiti to be simply wiped off, or even washed off by rain. This will significantly reduce maintenance costs associated with graffiti. Another method (slowly) garnering support is the allocation of walled areas to graffiti. This gives a sense of ownership to patrons of the public space. It also acts as a decoy, attracting graffiti artists/vandals away from other susceptible areas (Tracey, 2007). 15
  16. 16. 6. Conclusion It is important for a landscape architect to understand all threats posed to a site. It is only after analysis and understanding of plant knowledge and relevant environment can good design follow. A thorough SWOT (strengths, weaknesses, opportunities and threats) analysis is vital at this stage. By studying the remedial and preventive measures and controls, as previously described, a landscape architect will be able to create an effective design with successful implementation of protective measures (McLennan, 2004). However, knowledge of pest and disease and vandalism controls is still only a small part of design; it still does not guarantee the creation of an effective design. Public spaces that have become dilapidated due to vandalism or pests and disease, are the by-products of bad design. Proper planning and anticipation of problems are essential to the long term success of a design. However, of all the methods described above, none would be truly effective by themselves alone. It takes a planned integrated system of strategies and management. Suitability, compatibility, effectiveness, sustainability and affordability are all questions to consider and answer before implementation (Bird, 2004). All the while complementing the design and remaining aesthetically pleasing. It is no longer a matter of choice; it is a necessity for public spaces to maintain their intended use and appearance. Sustainable, low energy input controls are the way forward for public spaces. These will be integrated control schemes using several systems. The reasons for this are the current economic climate and the use of organic controls over chemical. These systems will result in less manual labour in terms of maintenance and an increase in biodiversity as a positive side effect. Chemical controls have high costs in terms of materials, equipment, and labour and can damage the surrounding environments (Brickell, 2002). In terms of vandalism, people who want to vandalise, will do so. The amount of damage done and cost incurred will be up to the designer. Physical barriers retro fitted into designs upset the layout of the public space. They appear ugly and out of place. If physical barriers are used they should be integrated and made part of the design. CCTV points are a last resort and give a sense of danger instead of safety. With all the thought and effort put into a design to curb vandalism, it is ultimately up to those in control post design and the programs they implement (Goldstein, 1996). 7. Opinion Through working on this project i have learned and understood the problems affecting public spaces, in context to vandalism, pests, disease and disorders. It is through this understanding of their causes, effects & controls that I have formed my own opinion on how a landscape architect would counter their effects and damage through design. Personally, I believe that the use of chemicals is an admittance of bad design and poor preparation. Chemical controls should only be used as a last resort. They pose a serious health risk to the environment, especially in public spaces. Organic controls (i.e. companion planting, permaculture, etc) allow for natural succession and replicate nature, making a planting system all the more natural and less tamed, artificial. Of course organic controls need to be designed into an integrated control scheme to be truly effective. 16
  17. 17. On the subject of vandalism, in all its forms, must be accepted to a certain degree as inevitable. Good design can remove hotspots for anti social behaviour, yet it is up to the local community to respect their own public space. I believe the encouragement of certain forms of vandalism can be beneficial however. It will lead to personalisation of the public space and give a sense of ownership to the community. These forms of vandalism include street art and guerrilla gardening. Ultimately the best control is the public themselves. By involving the local population in the design as much as possible, it will deter any sense of isolation or disrespect towards the public space. I have come to the conclusion that, in my own opinion, by understanding a site and its surroundings (along with all its abiotic, biotic, economic and social factors) through research and analysis, a competent landscape architect will formulate a successful design that can stand the test of time. A landscape architect must anticipate all possible problems and formulate their solutions to the best of his/her ability. 8. Proposal 8.1 Design Statement “To create an area that invites users into the space & exudes a sense of safety. The space invites the user as an escape from the chaos of urban life”. 8.2 Design Elements and Rational Two of the existing planting beds will be replanted with appropriate selections. These will include pollution tolerant trees (London Plane), pest repellents (Lavender) & plants that increase bio-diversity. These attributes will counter physiological disorders (caused by pollution), deter disease and control pest numbers. This planting philosophy is influenced by the practice of companion planting. New beds will also be created in the public space. These will be cut out of the existing concrete paving. The paving will then be recycled (up to 40%) and crushed. The designated areas will act as a brownfield site. These beds will then be planted with sedums and other alpines. The site will also be sown with wildflower seeds. Brownfield sites act as important habitats for many invertebrates and birds. The diversity of the wildflower mix and natural succession that follows will attract a high number of beneficial invertebrates to the public space. The wildflowers will create a polyculture, becoming resistant to any rampant disease or pest. The addition of recycled rubble from the site will increase drainage and carry pollutants away from the soil surface (Porosity). The brownfield site creation will save cost compared to ordering in topsoil to the site. Alpine plants will also be located in the brownfield beds. Saxifraga urbium and Sedum acre aureum have been chosen for their ability to thrive in poor, well drained soils. Lighting is introduced into the design to brighten up the public space at night. The design is also quite open and allows for clear visibility. The focal point of the design is the raised bed/seating area. 17
  18. 18. 8.2.1 Plant List 1. Platanus x acerfolia “Columbia” (Pollution tolerant) x 3 2. Craetagus monogyna x 5 3. Cotoneaster “Rothschildianus” (Tolerant of poor soil/groundcover) x 8 4. Ceanothus thyrsiflorus repens (Groundcover) 5. Lavanduala angustifolia “Hidcote” (Pest repellent) 6. Hebe “Autumn Glory” (Frost hardy/evergreen) 7. Olearia haastii (Frost hardy/beneficial insects) x 1 8. Nepeata faasenii “Six Hills Giant” 9. Wildflower mix 10. Sedum acre aureum 11. Saxifraga urbium 18
  19. 19. 9. References Banksy (2006). Wall & Piece. London: Century. p1-2, p130. Bird, R (2004). Garden Basic: Companion Planting. London: Quantum Publihing. p12-15, p52-61. Bell, P (2002). Pests & Diseases of Horticultural Crops. Piltown, Co. Kilkenny, Ireland: Teagasc. p2, p37-51, p56-59, p73-95. Brickell, C (2002). The Royal Horticultural Society Encyclopedia of Gardening. 2nd ed. London: Dorling Kindersley. p639-657. Christiansen, M L. (1984). Vandalism Control Management for Park Districts . Available: http://www.lib.niu.edu/1984/ip840120.html. Last accessed 4th October 2010. Fuller, J. (2008). How Xeriscaping Works. Available: http://home.howstuffworks.com/lawn- garden/professional-landscaping/alternative-methods/xeriscaping.htm. Last accessed 4th Goldstein, A.P. (1996), The Psychology of Vandalism. New York: Plenum Press. p1-17, p50- 70. Lamb, R. (2008). How Permaculture Works. Available: http://home.howstuffworks.com/lawn-garden/professional-landscaping/alternative- methods/permaculture.htm. Last accessed 4th Secured by Design. (2004). Secured By Design Principles. Available: http://www.securedbydesign.com/pdfs/SBD-principles.pdf. Last accessed 4th October 2010. Tracey, D (2007). Guerrilla Gardening: A Manualfesto. Canada: New Society Publishers. p19-35, p186-193. 19
  20. 20. 10. Appendix 10.1 Plant Pests Pest Name: Birds (Pigeons, Bullfinch, Sparrows etc) Symptoms/Damage: Ornamentals stripped of flowers & buds. Ornamental fruit eaten/attacked Treatment: Remove damage fruit (Stop spread of disease/fungi) Control: Netting &/or mechanical scarers History/Description: While common garden birds are a welcome sight in most landscapes & parks, they can become problematic, especially where fruit trees are involved. Their waste can also become a slipping hazard in public spaces. Pest Name: Cats Symptoms/Damage: Bark damage, seed bed disruption, transplant failure Treatment: Application of Aqua-seal 50 to bark wounds (Stop fungal/disease infection) Control: Cat repellent spray, sonic deterrent, mesh wire netting History/Description: Stray Cats can become problematic in public spaces damaging trees while sharpening their claws & burning grass with urine. Deterrence & control is almost impossible. Pest Name: Deer Symptoms/Damage: Rose buds stripped, bark damage, new shoots damaged/eaten Treatment: Application of Aqua-seal 50 to damaged bark Control: Two metre high fences, mesh wire netting History/Description: Prevalent in rural areas mostly, Deer can do detrimental damage to trees & shrubs. They practice shaping their antlers on the bark & trample shrubs through their movement. Pest Name: Dogs Symptoms/Damage: Plants uprooted, conifer root damage, lawn scorched Treatment: Water area heavily after canine urination to combat lawn scorch effects Control: Mesh wire fencing, deterrent dusts, repellent sprays History/Description: Bitch urine disfigures lawns & the base of conifer trees is a location of choice for most dogs because of its insulation values. Like cats, it is almost impossible to 20
  21. 21. control damage done by dogs, short of keeping them separated from the affected area entirely. Pest Name: Fox Symptoms/Damage: Lawn/Shrub scorch, conifer damage, dustbins/skips disturbed Treatment: Water area heavily after canine urination to combat lawn scorch effects Control: Spray repellents, Mechanical scarers History/Description: Common in rural areas & towns, foxes are problematic. There is no 100% way to combat or deter them. Pest Name: Mice & Rats Symptoms/Damage: Burrows, wall damage, fruit damage, seed removal Treatment: / Control: Baited traps, sonic repellent, predatory species introduction History Description: Problematic & unhygienic, mice & rats can damage fruit & attack plants to eat un-fallen seeds. Contact a local exterminator if rats are discovered. Pest Name: Rabbits Symptoms/Damage: Brown patches on lawn, shrub damage, tree bark damage Treatment: Application of Aqua-seal 50, removal of affected lawn & replace with new turf or re-seed Control: Individual tree guards, sonic/spray repellent History/Description: Problem in rural areas, deterrents & controls soon lose their effectiveness. Individual tree/shrub protection proves effective. Burrowing remains a problem. Pest Name: (Grey) Squirrel Symptoms/Damage: Bulb destruction, removal of buds, shoot tip damage, tree bark stripped Treatment: Application of Aqua-seal 50 to bark wounds Control: Mechanical scarers, net covered cages, tree guards History/Description: All squirrels cause damage, but none more so than the Grey squirrel. Oak trees are quite often the victim of having their bark stripped. Also, the Grey squirrel carries a virus that attacks the rarer Red squirrel, yet the Grey squirrel is immune to this virus. 21
  22. 22. Pest Name: Aphid (Greenfly) Symptoms/Damage: Loss of vigour in growth, distortion of leaves/shoots, Honeydew accumulation Treatment: Systemic Insecticide, or a safer option of insecticidal soap. May require more than one application Control: Application of insecticidal soap or a biological control by means of the introduction of natural predators (Ladybird) History/Description: Aphids are among the most problematic & commonest pests. They have a number of species which vary in colour, but all do the same damage. Only a small amount of plants are immune to their actions. They work by sucking the sap out of new growth in the spring & move on to the feeding of leaves in following months. The accumulation of sap (Honeydew) on the leaves leads to the colonisation of Sooty Mould (Secondary infection). Pest Name: Capsid Bug Symptoms/Damage: Holes in leaves, Brown spots on leaves, brown/withered buds Treatment: Systemic insecticide (Bifenthrin) or insecticidal soap Control: If identified, avoid disturbance before application of treatment. Capsids move rapidly & spread to surrounding plants if disturbed. Better to localise the problem & eliminate it. History/Description: Not as common as Aphids & rarely become as serious a problem to require treatment. Mainly, they attack roses. Pest Name: Caterpillar Symptoms/Damage: Holes in leaves, leaves stripped Treatment: Spray with insecticide (Pyrethrins) if widespread, if not, knock off the caterpillars Control: Netting, Insecticidal soap History/Description: More common in the vegetable garden, Caterpillars still pose a problem to urban green-spaces. They may leave shrubs defoliated & plants stripped of all their leaves, with just the leaf veins remaining. Larvae can also be problematic. Pest Name: Cockchafer Beetle Symptoms/Damage: (Grub) Roots eaten, plant wilt, (Adult) Irregular shaped holes in leaves, damage to rose buds 22
  23. 23. Treatment: Insecticidal spray (Bifenthrin), Insecticidal soap Control: Netting, Insecticidal soap History/Description: 4cm in size. Significant damage is caused to the plant by the grub & adult. Tlling of the soil before planting will remove any larvae present. Pest Name: Leaf Miner Symptoms/Damage: Holes in leaves, weak leaves, “tunnels” visible in the leaf, occurrence of brown blisters Treatment: Minor problem, application of an insecticide is uncalled for. Control: Remove & destroy leaves. Infected leaves must not be composted, burn leaves. History/Description: Trees affected by Leaf Miner are Holly, Lilac, Roses, Privet, Honeyshuckle & Azalea. “Mines” are produced by grubs burrowing their way through the leaves, feeding until they mature. Pest Name: Red Spider Mite Symptoms/Damage: Red/Bronze appearance of leaves accompanied with webbing threads. Treatment: Application of Bifenthrin every 3-4 weeks depending on scale of problem & weather Control: Insecticidal soap History/Description: Common on the underside of leaves. Prevalent on roses & conifers. The problem of Red Spider Mites peak in warm humid weather, as the convection currents ease their movement & spread. Pest Name: Scale Insect Symptoms/Damage: Loss of plant growth/vigour, yellowing of leaves Treatment: Application of Thiacloprid in late Spring Control: Insecticidal Soap History/Description: Occur mostly on tree branches & large shrubs. Often hard to spot, due to their low mobility. Often, most adults spend their entire lives in the same spot. Pest Name: Thrips Symptoms/Damage: Blackened leaf/petal edges, flower/leaf disfigurement Treatment: Insecticidal soap Control: Keep plants well watered in hot, humid weather 23
  24. 24. History/Description: Tiny, 4 winged insects. Only considered a problem where roses are concerned. Associated with warm, humid weather. Also known as Thunder Flies. Pest Name: Tortrix Moth Symptoms/Damage: Curled/rolled leaves wrapped in silken threads, adjacent leaves woven together Treatment: Removal of affected leaves Control: Insecticidal soap, protective netting History/Description: Caterpillars roll leaves of plants together with silk threads. In this protective shelter they feed on the leaf & plant tissues. Most active during mid-Summer. Pest Name: Vine Weevil Symptoms/Damage: U-shaped holes/notches on leaf edges, damage to the roots of container plants by the grubs Treatment: Spray with a contact insecticide Control: Insecticidal soap, tilling of soil before planting History/Description: Grubs are problematic with potted plants & large containers. The adults mostly attack waxy leafed evergreens (Rhododendrons, Azaleas, Camellia). Vine Weevil spread & move quite fast so spraying proves ineffective. Pest Name: Wireworm Symptoms/Damage: Roots of plants damaged/eaten, stems tunnelled through Treatment: None Control: Proper soil preparation & tilling are the only way to destroy this pest. History/Description: Located underground. Slow moving, but cause massive damage, especially to perennials in borders adjoining grassland. Wire worms eat the roots & tunnel their way up through the stem of the plant. 10.2 Plant Diseases and Disorders Name: Bacterial Canker Symptoms/Damage: Sap/gum oozing from site of infection/wound, brown circular spots & holes on the leaves, dead branches 24
  25. 25. Treatment: Remove & destroy infected branches. Cut back branches to a non-infected area. Spray infected trees with a copper compound from August through October. Control: Application of Aqua-seal 50 to tree wounds History/Description: Bacterial Canker is caused by a secondary infection. Bark wounds become infected by the causing bacteria. Wounds should immediately be treated with Aqua- seal 50 which blocks bacteria & fungi from infecting the wound. Affects ornamental fruit trees (Cherry, Plum, Almond, etc). Name: Canker Symptoms/Damage: Cracked, caved in bark. Bark usually shrinks around the base of an adjoin branch. The branch will die if the canker surrounds it’s base. Treatment: Remove infected branches Control: Application of Aqua-seal 50, burn removed branches to stop spread of infection History/Description: Attacks a wide range of woody plants. Can also be a problem in roses. Name: Blossom Wilt Symptoms/Damage: Wilting of flowers & leaves, brown discolouration, presence of grey mould Treatment: Remove infected areas of the plant(s) Control: None History/Description: Caused by a fungal infection that is preceded by a wet Spring. Serious problem with ornamental fruit trees. Spraying proves ineffective. Name: Bud Blast Symptoms/Damage: Flower Buds turn brown, presence of fungus like black bristles, easy to distinguish from frost damaged buds as they remain firmly attached. Treatment: Remove infected buds & destroy Control: The infection is secondary, with the primary wounds & damage being caused by Leafhopper insects. Spraying for these insects in August with a contact insecticide will prevent the problem. History/Description: The disease only infects Rhododendrons. Infected buds do not rot & are not easily removed. Name: Clematis Wilt 25
  26. 26. Symptoms/Damage: Wilted shoots, followed by sudden death. Spreads from one infected shoot to the other. Often area of infection is at base of plant. Treatment: Avoid damage to the stem (secondary infections). Remove & destroy affected shoots. Control: None History/Description: Clematis Wilt is a secondary infection caused by a fungal disease. It is devastating to the larger flowered varieties of the Clematis family. Infection often spreads from shots growing at the base of the plant. Name: Crown Gall Symptoms/Damage: Wart/Blister like growths on the lower stems & root crown. Brown in colour, with a “bubbly” appearance. Can kill the tree if a ring of Galls is allowed to form. Treatment: Remove the site of infection & affected area. Spray with Copper fungicide & apply Aqua-seal 50 to the wound. Control: Pre-treatment spray on unaffected trees in October. History/Description: Crown Gall is a blister like formation caused by secondary infection bacteria. The disease usually occurs on young trees in waterlogged soil. Although it can become problematic on mature trees if a ring of Galls is allowed to form. Name: Dutch Elm Disease Symptoms/Damage: Defoliation (yellowing of leaves) during the growing season. The Leaves then turn brown, but do not fall. Branches become distorted & curled. Treatment: Cut out infected branches & burn Control: Remove & destroy infected trees to avoid spread of the disease History/Description: Dutch Elm Disease is a menace that spreads & kills quickly. All infected wood/trees must be destroyed. Even if the tree is dead, the disease is not & will spread by wind or mechanical means (animals/invertebrates). Name: Coral Spot Symptoms/Damage: Whitish pink spots/blisters on branches & main stem. Treatment: Remove & destroy all infected areas Control: Remove all dead wood from site & burn all cuttings 26
  27. 27. History/Description: Coral Spot is a fungal disease that enters the plant through an open wound. However, the fungus begins life by colonizing fallen dead wood &/or cuttings on the ground. From here it spreads to leaving trees & shrubs. The disease can prove fatal to plants. Name: Fireblight Symptoms/Damage: Wilted, brown leaves that do not fall. Presence of Canker on the branches. Treatment: Remove infected branches, plus 60cm of healthy branches to avoid spread. Control: Burn all cuttings, dead wood & fallen trees. Contact the appointed government authority (Coillte, Teagasc). Destroy surrounding trees you suspect of infection. History/Description: Fireblight is a destructive & easily spreadable disease. It is mandatory, by law, that you contact the local government authority if you suspect Fireblight. Fireblight mainly affects trees & shrubs of the Rose family, but truly, no plant is safe. Fireblight spreads by bacteria in the wind. If infection spreads from the branches to the main stem/trunk, the tree will die. Dead trees & cuttings infected by Fireblight must be burned in an effort to halt or at least, slow down the spread of the disease. Name: Phytophthora Symptoms/Damage: Plant death, undeveloped leaves, die back, blackened roots Treatment: None Control: Burn infected plants, Improve soil drainage History/Description: A soil borne fungus occurring in waterlogged areas. The fungus infects roots near the stem of the plant & from there infect other roots & eventually other plants. There is no treatment for the disease. Waterlogged sites should be avoided & the soil amended before use. Name: Powdery Mildew Symptoms/Damage: Leaves covered in a fine, white, patchy powder. Treatment: Cut out affected areas Control: Avoid overplanting in small spaces History/Description: Common in moist, warm, humid weather. Spreads easily in overcrowded plant beds. Usually, it is not fatal to the affected plant. Name: Rust Symptoms/Damage: Yellowish brown blisters on the underside of leaf 27
  28. 28. Treatment: Spraying proves ineffective Control: Remove & destroy infected areas History/Description: A non-fatal disease. It affects Birch, Rhododendrons & Mahonia. The blister(s), on the underside of the leaf, produce spores that spread the infection. Name: Shot Hole Disease Symptoms/Damage: Appearance of brown spots on the leaves, which then fall out leaving holes. Treatment: None Control: The attacking fungus is only problematic on weakened trees. Avoid this by feeding & regular care. Burn fallen leaves to hinder the spread of the disease. History/Description: Shot hole disease becomes a problem on ornamental cherry trees. This, however, can easily be avoided by providing the conditions it needs to grow strong. The brown holes in the leaves are dead parts of the leaves. As the leaf grows, the dead spots do not. The infected areas fall from the leaves. This is how the fungus spreads. Name: Viruses Symptoms/Damage: Variegated leaves, blotchy yellow spots, streaked flowers, stunted growth & crinkled leaves Treatment: None Control: Keep aphids to manageable levels, as they carry many viruses. History/Description: Viruses is a generic term for the many diseases that fall under this sector. Few shrubs & trees are susceptible to infection. Yet, there is no cure for the ones who are. Some plants are purposely infected by viruses by growers for aesthetic reasons, i.e. Acuba japonica. Name: Algae Symptoms/Damage: Accumulation of green black slime on the surface of lawns. Treatment: Ferrous (Iron) Sulphate Control: Aerate soil in Early Autumn & topdress with Lawn Sand. History/Description: Algae growth on lawns is a clear indicator of poor drainage. Algae appears alongside areas of moss & along the “Drip-Line” of trees. Applications of lawn feed can give lawn grass a competitive advantage to occupy optimum sites for Algae growth. 28
  29. 29. Name: Dollar Spot Symptoms/Damage: Circular brown patches on lawn Treatment: Application of a high Nitrogen fertiliser Control: Aerate soil in early Autumn History/Description: Dollar Spot is a fungal disease that affects Creeping Red Fescue & other fine leaved grasses. The circular patches eventually join together & destroy the appearance of the lawn. Name: Fairy Ring Symptoms/Damage: Rings of dark green grass appear, surrounding a circle of dead, brown grass. Most fairy rings are accompanied by mushrooms. Treatment: Application of a high Nitrogen Fertiliser. This only masks the problem, as it darkens the surrounding, unaffected grass. Control: Removal of topsoil from affected area. History/Description: They’re several types of Fairy Rings, each with varying degrees of impact. There are no treatments or cures for fairy rings. Complete turf replacement is the only effective method. Name: Fusarium Patch Symptoms/Damage: Round yellow patches appearing on the lawn. Presence of white mould at edges of infected area. Treatment: Application of Nitrogen rich fertiliser Control: Aerate soil in early Autumn History/Description: The most common disease of lawns. Occurs in Autumn &/or Spring. Nitrogen rich fertilisers must not be applied in Autumn. Name: Red Thread Symptoms/Damage: Appearance of bleached patches, which turn pink. Treatment: Application of high Nitrogen fertiliser in Spring Control: Soil aeration History/Description: Occurs in irregular patches on starved, nutrient deficient lawns. Unpleasing to look at, fortunately it is non-fatal. 29
  30. 30. Name: Chlorosis Symptoms/Damage: Yellowing of leaf tissue. Either between the veins (Magnesium deficiency) or the entire leaf (Iron/Manganese deficiency) Treatment: Application of fertiliser & peat (improves drainage) Control: Proper soil drainage management History/Description: Many forms of Chlorosis exist, each caused by a lack of certain Macro/Micro nutrients. Lime induced Chlorosis occurs in Acid loving plants growing in Alkaline soil. Name: Nitrogen Deficiency Symptoms/Damage: Small, undeveloped, pale leaves Name: Potash Deficiency Symptoms/Damage: Brown leaves, which are very brittle. New shoots turn downwards. Name: Manganese Deficiency Symptoms/Damage: Browning between leaf veins Treatment: Application of 10:20:20 fertiliser & well rotted manure. History/Description: Low Cation Exchange Capacity (C.E.C.) in soil causes vital nutrients to be washed out of the soil by heavy rain. Improvement of soil structure is the only long term treatment. Manganese deficiencies are often caused by high levels of Potash in the soil. 10.3 Companion Planting Name: Chamaemelum nobile Attribute: Attracts Hoverflies, Wasps Controls: Aphids, Blackfly Name: Hedera helix Attribute: Attracts Hoverflies, Wasps Controls: Aphids, Blackfly Name: Helianthus species Attribute: Attracts Lacewings, Wasps Controls: Aphids, Blackfly. Also acts as a Decoy plant, drawing several pests away from planting susceptible to pest damage. 30
  31. 31. Name: Tagetes erecta Attribute: Repels Nematodes Controls: Reduces damage to planting Name: Tagetes patula Attribute: Repels Nematodes Controls: Reduces damage to planting Name: Solanum nigrum Attribute: Poisonous, attracts adult Colorado beetle to lay its egg around plant roots. Acts as a decoy plant. Controls: When eggs hatch, the larvae eat the poisonous roots of the plant, reducing the number of Colorado beetles in the vicinity Name: Allium schoenoprasum Attribute: Cures Blackspot on Roses, repels Japanese beetles Controls: Disease, Japanese beetles Name: Anethum graveolens Attribute: Repels aphids & red spider mites Controls: Gall disease on trees on woody shrubs, which is manifests after primary wounds caused by red spider mite Name: Eucalyptus species Attribute: Repels broad range of insect pests (& predators) Name: Allium sativum Attribute: General insect repellent 31
  32. 32. Name: Tropaeolum majus Attribute: Repels aphids, Colorado beetles & Whiteflies Controls: Reduces local pest population Name: Rosemarinus officinalis Attribute: General insect repellent Name: Salvia officinalis Attribute: Repels root maggots Controls: Reduces damage to root systems of plants Name: Lavanduala species Attribute: Repels Aphids Controls: Reduces local Aphid populations Name: Thymus vulgaris Attribute: Repels Whitefly, Aphids Controls: Protects local planting system from pest damage Name: Medicago sativa Attribute: Acts as a Decoy plant Controls: Lygus bugs Name: Chenopodium album Attribute: Acts as a Decoy plant Controls: Leafminers Appendix C (Problems of Vandalism) 32
  33. 33. Name: Graffiti Rate of Occurrence: Common Areas Affected: Smooth surfaces, Walls, Structures Solution: Paint over affected area, Pressure wash affected area clean Prevention: Use Rough Textured walls, Treat walls with a water borne coating, Green walling Name: Tree Damage Rate of Occurrence: Uncommon Areas Affected: Pathways, Planting systems Solution: Replant/repair tree, prune damaged branches, application of Aqua-Seal 50 Prevention: Fencing off tree 33

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