Need Assistance? 01384 442752 (UK)


Duration (approx) 100 hours
Qualification Statement of Attainment

Learn about Plant Health

  • Learn about the causes of poor plant growth or damaged tissues.
  • Understand how extreme cold, heat, wet or dry can impact a plant.
  • Determine how to minimise the effects of infections, insects or other pathogens.

Student Comment:  "I have found the course to be interesting and challenging, with great learning materials that really make you research the industry and get involved. It has been a great way to study because it has allowed me to work in the industry and study at the same time. I have found the online resources to be fantastic, the tutor's feedback constructive and the fact that assignments can be submitted online makes the process so easy."
Tom Wood - Diploma in Horticultural Science

It's easy to enrol...

Select a payment plan:  

Select a learning method  


Understand the Contributors to Plant Health

An advanced course specialising in the care of plant health.

  • Understand plant health.
  • Identify health problems in plants.
  • Learn about techniques to control problems in plants.
  • A useful qualification for anyone wanting to work in the plant industry.
  • Learn from highly qualified and experienced tutors.
  • Study in your own time and at your own pace.

There are thousands of possible causes which can contribute to a plant's problems.

More often than not, there are several factors involved. Minor diseases or environmental problems may weaken the plant, making it susceptible to some more major (obvious) disorders.

When you inspect a plant for problems, you should systematically consider all of the things which might possibly be going wrong. This course provides the foundation for inspecting diagnosing and treating all types of problems.

This subject develops a firm understanding of plant health, the systematic identification of health problems in plants, and the techniques for control of those problems.

Government, nursery and private positions are more demanding than they ever were; employers are becoming increasingly selective choosing personnel with broad horticultural knowledge and less emphasis is placed on the 'learn on the job' approach of years gone by. Education is imperative if you expect to compete in this field and those that have the knowledge will also have the best chance of reaping the rewards.

A sick plant may have one or several causes at the same time.


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


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 (i.e. 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;
    • 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.

What This Course Can Do For You

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 and Gardens
  • Garden Tourism
  • Garden Conservation
  • General Horticulture
  • Nursery and Propagation

Student Comment: "I have found the course to be interesting and challenging, with great learning materials that really make you research the industry and get involved. It has been a great way to study because it has allowed me to work in the industry and study at the same time. I have found the online resources to be fantastic, the tutors feedback constructive and the fact that assignments can be submitted online makes the process so easy." 
Tom Wood - Diploma in Horticultural Science

Enrol today and start learning!

You can start the course at any time.  Study when and wherever you want to with our online and USB study options.

If you have any questions about the course or studying with ACS, please get in touch using our Free Course Counselling service.

Courses can be started anytime from anywhere in the world!

Meet some of our academics

Rosemary Davies (Horticulturist)A graduate of Burnley Horticultural College; Rosemary has over 30 years of experience in horticulture. Her training was extensive covering both amenity and production horticulture; developing pactical skills and a deep understanding of the sciences that underpin horticulture. She worked with the Agriculture Dept in Victoria as a consultant or advisor to both farmers and home gardeners. Over the years, her experience has been as broad as her training, working on radio with ABC radio, a garden editor (with several major publications) and as a teacher, writer, garden designer and consultant. Rosemary has led several garden tours to the UK and Europe. In 1999 Rosemary was BPW Bendigo Business Woman of the Year and is one of the founders and the Patron, of the Friends of the Bendigo Botanic gardens. She has written six gardening books and collaborated on many others. Rosemary brings a unique personality, knowledge base and passion to the school; an an infectious love of horticulture in support of our students. She holds a B.Sc Hort,, Dip.Hort.Sc., Dip. Advertising & Marketing and B.Ed.
John Mason (Horticulturist)Horticulturist, Nurseryman, Landscaper, Garden Writer, Parks Manager and Consultant. Over 45 years experience; working in Australia and the UK. He is one of the most widely published garden writers in the world; author of more than 100 books and editor for 4 different gardening magazines. John has been recognised by his peers being made a fellow of the Institute of Horticulture in the UK, as well as by the Australian Institute of Horticulture.
Diana Cole (Horticulturist)Horticulturist, Permaculturist, Landscaper, Environmentalist. Holds a Diploma in Horticulture, degree in geography, permaculture certificate and various other qualifications. Between 1985 and 94, Diana was a task leader with the British Trust for Conservation Volunteers. Since 2001 she has been chairperson of the Friends of Mellor Park (with Stockport MDC). From 2005 she has worked exclusively in horticulture as proprietor of her own garden design and consultancy business in and around Derbyshire; and at the same time as part time manager of a small garden centre. Diana has been an enthusiastic and very knowledgeable tutor with ACS since 2008.
Yvonne Sharpe (Horticulturist)Started gardening in 1966, studied a series of horticulture qualifications throughout the 1980's and 90's, culminating in an RHS Master of Horticulture. Between 89 and 1994, she worked teaching in horticultural therapy. Founded the West Herts Garden Association in 1990 and exhibited at Chelsea Flower Show in 1991. In 1994, Yvonne joined the staff at Oaklands College, and between 1996 and 2000 was coordinator for all Amenity Horticulture courses at that college. Since leaving Oakland she has been active as a horticultural consultant, retail garden centre proprietor and sessional lecturer (across many colleges in southern England). In 2000, she also completed a Diploma in Management.

Check out our eBooks

Rhododendrons and AzaleasGrow & Know Rhhododendrons and Azaleas by John Mason
Getting Work in HorticultureExplore what it is like to work in horticulture; how diverse this industry is, how to get a start, and how to build a sustainable, long term and diverse career that keeps your options broad, so you can move from sector to sector as demand and fashion changes across your working life.
Plant Pests & DiseasesAre you one of those people that kill every plant you touch? Perhaps it's not you. Perhaps it's a pest or disease. A little bit of reading might just turn your garden into an oasis. Learn how to identify pests and diseases and bring the spring back into your plant...visit the bookshop to find out more...
What to Plant WhereA great guide for choosing the right plant for a particular position in the garden. Thirteen chapters cover: plant selection, establishment, problems, and plants for wet areas. Shade, hedges and screens, dry gardens, coastal areas, small gardens, trees and shrubs, lawns and garden art.