Learn how to identify and treat plant health problems

Gardeners who can identify and control pests and diseases are always in demand. However it is not just gardeners that benefit from this valuable knowledge  - nursery staff, garden designers, grounds staff, park rangers, arborists, and council contractors all need to attain this knowledge to do their jobs effectively: gardeners can find solutions; nursery staff can advise their customers; garden designers can choose resistant species; ground staff can identify problems; and contractors can choose the right control methods!
This course develops a firm understanding of plant health, the systematic identification of health problems in plants, and the techniques for control of those problems.

Learn to identify and respond to health problems with plants

Pests and diseases can severely affect the productivity or appearance of plants; but these are not the only things that can affect plant health. Learning to identify health problems is the fist step toward overcoming them; but understanding what might potentially go wrong with a plant, can be the best way to minimise the risk of problems ever getting out of hand at all.


There are ten lessons in this module, as follows:

  1. Introduction
  2. Overview of Preventative Controls
  3. Insecticides
  4. Other Pesticides
  5. Spray Equipment
  6. Insect Biology
  7. Fungal Biology
  8. Environmental Problems
  9. Viruses
  10. Nematodes, Molluscs and Crustaceans


Duration: 100 hours


  • Here is just a sample of what you will learn to do in this course:
  • 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.



Here are just some of the things you will be doing:

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 life cycle of an insect species.

Explain how an understanding of insect life cycle 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.


Employers are always on the look out for knowledgeable horticulturists - not every graduate has the foundation knowledge that this course offers.

This course builds on knowledge gained through our Horticulture I and Horticulture II modules but may be taken as a stand-alone course. Those completing this course will have acquired a thorough knowledge of plant health to complement their understanding of general horticulture principles and practices. By understanding plant pest and disease cycles you will be better equipped to establish suitable programs of control for these problems. The course will suit people looking to work in:


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





Just go to the top of this page for pricing and enrolment options. If you have any questions you can contact us now, by:
Phone (UK) 01384 44272, (International) +44 (0) 1384 442752, or

Email us at [email protected]