Horticulture III (Plant Health)

Lesson Structure

There are 10 lessons in this course:

1. Introduction
   • Pests
   • Diseases
   • Common terminology
   • Diagnosing problems systematically
   • Tell tale symptoms
   • Conducting an inspection: four steps
   • Pest or disease reviews
2. Overview of Preventative Controls
   • Introduction
   • Methods of pest management
   • Integrated pest management
   • Cultural control
   • Using disease resistant varieties
   • Crop rotation
   • Timed planting
   • Mulching
   • Cleanliness
   • Biological control
   • Types of biological controls
   • Beneficial plants
   • Trap or decoy plants
   • Pheromone traps
   • Physical controls
   • Traps
   • Repellents
   • Mulching
   • Pruning
   • Wounds
   • Chemical controls
   • Understanding pesticides
   • Safely storing chemicals
   • Safely mixing chemicals
   • Legalities
   • Plant breeding for resistance
   • Sources and causes of resistance
   • Adaptability, resistance and pest variability
3. Insecticides
   • Types of insecticides: systemich, stomach poisons, contact poisons, etc
   • Inorganics, botanicals, organophosphates, carbamates, synthetic pyrethroids
   • Characteristics of insecticides: toxicity, spectrum, LD50, persistence, volatility, etc.
   • Golden rules for handling pesticides
   • Terminology
4. Other Pesticides
   • Chemical Pesticides: introduction
   • Review of common pesticides
   • Soil treatment for control of diseases
   • Soil pests
   • Types of fumigants
   • Systemic fungicides
   • Comparative toxicities
5. Spray Equipment
   • Types of sprayers
   • Uses of sprayers
   • Spray terminology
   • Sprayer maintenance and cleaning
   • Selecting a sprayer
   • Calibration
   • Using chemicals: agitation, clean up and disposal
   • Basic first aid with chemical pesticides
   • Response to liquid or powder spills
   • Keeping records
   • Misters, Dusters, Blowers
   • Pesticides and the environment
6. Insect Biology
   • Insect classification: orders, sub classes
   • Insect anatomy: mouthparts, legs, etc
   • Lifecycle
   • Feeding habits
   • Practical project: Insect collecting, preserving, identifying, for an insect collection
   • Common insects that a gardener encounters
   • Ants
   • Aphis
   • Beetles
   • Borers
   • Bugs
   • Caterpillars
   • Cockroaches
   • Crickets
   • Earwigs
   • Fleas
   • Flies
   • Galls (caused by insects)
   • Grasshoppers
   • Ladybirds (good and bad)
   • Leaf hoppers
   • Leaf miners
   • Lerps
   • Mealy bug
   • Mosquitos
   • Scale insects
   • Termites
   • Thrips
   • Wasps
   • Whitefly
7. Fungal Biology
   • What causes disease
   • Symptoms of disease
   • Lifecycle of a disease: inoculation, penetration, infection, growth and reproduction, dissemination
   • Fungi groups: obligate saprophytes, obligate parasites, facultative saprophytes, facultative parasites
   • Expanded concept of tree decay
   • Chemical pesticides in the UK and Europe
   • Common diseases
   • Anthracnose
   • Bitter pit
   • Blights
   • Botrytis
   • Canker
   • Cinnamon fungus
   • Club root
   • Damping off
   • Galls
   • Gummosis
   • Leaf curl
   • Leaf spot
   • Melanose
   • Mildews
   • Rots
   • Rust
   • Scab
   • Silver leaf
   • Spot
   • Smut
   • Sooty mould
   • Wilts
8. Environmental Problems
   • Common environmental problems
   • Foliage burns
   • Pollution
   • Lack of water
   • Drainage problems
   • Frost
   • Hail
   • Shade
   • Temperature
   • Wind
   • Symptoms of nutritional deficiencies
   • Air pollution
   • The plant and water
   • Non parasitic problems in turf (lawns)
   • Ways to provide environmental protection to plants
9. Viruses
   • Overview
   • Symptoms
   • Detection and diagnosis of viruses
   • Control
   • Examples of virus diseases
10. Nematodes, Molluscs and Crustaceans
    • Overview
    • Millipedes
    • Plant nematodes
    • Nematodes in citrus
    • Red spider mites
    • Spiders
    • Slaters or wood lice
    • Snails and slugs

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.

Aims

• Identify the characteristics of pests and diseases of plants.
• Explain methods for the control of pests and diseases.
• Describe the characteristics of a range of different pesticides, including insecticides and fungicides.
• Explain the selection and use of spray equipment appropriate for different specified tasks.
• Describe aspects of the biology of an insect which are relevant to pest control.
• Describe aspects of the biology of an fungus which are relevant to disease control.
• Explain how inappropriate environmental conditions can affect plant health.
• Identify the characteristic signs of a range of non-insect pests,and select appropriate control methods.

What You Will Do

• Develop a checklist for determining the significance of pests and diseases, which addresses different criteria including:
  • short term impact
  • long term impact
  • economic impact
  • aesthetic impact.
• Distinguish between the main types of plant diseases, including:
  • fungal
  • viral
  • bacterial.
• Create a standard worksheet for reviewing pest and disease problems of plants.
• Diagnose different problems (ie. pests or diseases), documenting the problem on a standard pest/disease review worksheet.
• Describe different ways to control pests and diseases, including:
  • Application of chemicals
  • Plant selection
  • Companion planting
  • Cultural techniques (i.e. improving ventilation, improving drainage)
  • Physical control (i.e. pruning, hand removal, trapping, hosing off).
  • Explain how plant breeding has been used to improve pest/disease resistance in different plant species.
• Explain three biological control methods for dealing with specific problems.
• Develop an IPM strategy for a specific situation such as a crop or garden, considering:
  • application procedures, remedial action and monitoring.
• Describe plant hygiene practices for a specific situation such as a crop, nursery or garden, in line with industry practice, enterprise guidelines and sound management practice.
• Recommend control methods for different pest and/or disease problems diagnosed.
• List safety procedures to follow when handling pesticides.
• Distinguish between the main groups of pesticides, including:
  • organo-phosphates
  • synthetic pyrethroids
  • carbamates
  • chlorinated hydrocarbons.
  • Explain the difference between the action of systemic and non-systemic pesticides.
• Explain maintenance practices, including cleaning, for a specified sprayer.
• List different uses for several types of sprayers, including a motorised pump sprayer, a knapsack and a PTO driven tractor mounted sprayer.
• Compare different sprayers, in terms of:
  • cost
  • applications
  • maintenance
  • spare parts
  • ease of use
  • safety.
• Explain the application of chemicals in a given situation, including:
  • Calibration
  • Mixing chemicals
  • Equipment operation
  • Safety measures
  • Post spray procedures such as cleaning, and storage of chemicals).
  • Describe the minimum records which should be kept when spraying pesticides.
• Prepare a labelled diagram showing the structural parts of an insect.
• Prepare an insect collection of different insects of significance to agriculture or horticulture.
• Identify to genus level, the insects collected.
• Compare the structural differences between different types of insects.
• Describe the lifecycle of an insect species.
• Explain how an understanding of insect lifecycle can be applied to pest control.
• Describe the lifecycle of a fungal disease species.
• Explain the physiology of tree decay processes, including compartmentalisation.
• Explain aspects of fungal biology, for different types of fungi, which are of horticultural significance, including:
  • Phytophthora
  • Sclerotinia rot
  • Peach leaf curl (Taphrina deformens)
  • Powdery Mildew
  • Pythium.
• List environmental problems which affect plant health and their symptoms.
• Describe the affect of air pollution on different plants.
• Identify nutritional deficiency symptoms in specified situations.
• Develop a fertiliser program in response to a specified nutritional problem.
• Distinguish between the affects of water deficiency and water excess on plant health.
• Explain how to diagnose damage by various non-insect pest problems, including:
  • Nematodes
  • Slugs and snails
  • Mites
  • Millipedes
  • Larger animals such as rabbits, possums or birds.
• Explain how to control different non-insect pests with both chemical and non-chemical methods.

If you want to know more about providing optimum care for plants, this course as an excellent foundation for learning to deal with any pest or disease problem.

Learn how to control plant pests,  diseases and other health problems for example:.

A hole in the leaf may indicate damage by a bacteria or an insect. If you thought the problem was caused by an insect and sprayed it with an insecticide, but it was actually caused by a bacteria, then the spray is totally wasted.

Plants can get sick just as easily as people.

The problems they encounter can include:

• PESTS...Animals of various sizes and forms

• DISEASES....Other living organisms (eg. fungi, bacteria and virus)

• ENVIRONMENTAL DISORDERS....Environmental factors (eg, drainage, pollutants, weather)

• NUTRITIONAL PROBLEMS....Too few, too many, or unavailable nutrients

• WEEDS....Undesirable plants creating problems for good plants

MORE THEN ONE PROBLEM?

Often your plants can suffer from more than one problem. Different problems are interrelated, with one causing others to develop. For example, poor drainage may result in damage to a plant's roots. This in turn can result in reduced vigor, opening the plant up to attack from various pests and diseases. These pests and diseases may be obvious, but the damaged roots may not. The most important problem is called the "primary problem" and other problems which can occur as the plant weakens, are called "secondary" problems. When you look for a problem, always remember; you might be looking for several answers (not just one).

How to Look for Symptoms

At the end of this course, you should be able to look at a plant, and notice things that are tell tale symptoms of a problem. You will be able to understand something of that problem, and through that understanding be able to seek the right information to confirm, or complete a diagnosis or at the very least, make an informed judgement about how the plant should be managed in view of what you discover.

TELL TALE SYMPTOMS

There are certain things that are tell tale symptoms for many different, common problems. When you inspect a plant, look for these things.

1. Wilting

• Insufficient water in the soil

• Too Hot -Leaves drying out faster than the water can be taken up

• Something stopping water going up the stem (eg: borer, disease, in lower part of plant) TAKE A CLOSER LOOK!

2. Yellow Leaves

IF OLDER LEAVES

• Lack of Nitrogen (feed with a nitrogen fertilizer)

• Lack of Nitrogen caused by wet soil ‑wet soil stops nitrogen being taken into the plant (improve drainage or cut watering).

• Chemical damage. Over-spray from herbicides is the most common damage of this type.

• Soil very dry. Often the edges (or margins) of the leaves will show signs of curling up or browning off.

IF YOUNGER LEAVES

• Iron deficiency.

• Other nutrient deficiency. Consider when the plant might have been mulched or fertilized last. Consider how rich or poor the

• soil looks (not just on the surface, but dig down a little). Consider if there are earthworms present or not.

• Chemical damage. Consider what chemicals have been used in the vicinity; not just recently, but even decades ago. Consider if there is any builders debris about.

3. Look to see if the damage is distributed evenly over the plant. Is it:

• On one side only.

• On the top only.

• On the most exposed parts.

          ..........IS THERE A PATTERN?

4. Look to see if damage has only just happened....or did it occur some time ago?

• The appearance of the growing tips tells you the current condition.

• Young shoots indicate a healthy plant overcoming past problems.

• Excessive side shoots lower down indicates disruption of hormone flow in the plant, or some other problem in the upper parts of the plant.

AFTER YOUR STUDIES

This course builds on Horticulture I and Horticulture II but may be taken as a stand-alone module, although it assumes some general horticulture knowledge or learning. Graduates of this course will be well versed in all aspects of plant health to complement their plant knowledge and appreciation of general horticulture principles and practices. If you complete this course you will be able to demonstrate a higher level of understanding of plant pest and disease problems through awareness of the biology of pest and disease cycles. This is imperative when setting up programs for prevention and control. The course is suited to people working in:

General horticulture
Garden maintenance
Parks & gardens
Garden conservation
Garden tourism
Nursery & propagation