Integrated pest management in greenhouses

Integrated pest management (IPM) is a term most people involved in horticulture will have heard. IPM is a package of interchangeable good agricultural practices that can be used to manage pests in the crop. The most important thing to note is the word integrated.

Key practices which need to be observed for IPM are sanitation and hygiene, monitoring, record keeping, using less chemicals and more common sense and choosing newer chemistry chemicals that tend to be pest specific or lower toxicity.

Too often growers (and even their advisors) focus just on biological controls (predators, parasites and pathogens) when considering an IPM approach but it is essential to recognise that IPM encompasses the combination of cost-effective cultural, physical, chemical and biological management strategies that prevent, suppress or control pests and diseases. These strategies have minimal hazards and risks to the health and safety of crops, people and the environment. The use of synthetic pesticide sprays is only undertaken when all other alternatives have been considered and exhausted – chemicals, especially broad spectrum old chemistry pesticides are a last resort.

IPM is based on keeping pest populations to levels which the crop and fruit yield and quality can tolerate. It is about taking action to manage pests when they are at their most vulnerable life stage(s). IPM is not about accepting a financial loss instead of controlling a pest.

Effective pest management requires correct identification of the pest in it’s different life stages and regular, routine monitoring of pest populations.

Routine monitoring for pests allows you to act to manage pests in a timely manner. Management decisions are based on the stage of crop growth as well as the actual pest population levels. This is more efficient than the conventional calendar spraying and can result in better economic returns.

Always keep written records of pest numbers, their distribution in the greenhouse, the level of damage and stage of crop growth. Overtime, these records become the basis for benchmarking your production system and become invaluable in working out action thresholds for your major pests. Records are also an objective performance review of any corrective action taken.


Sanitation is the first step in managing any pest. You should always start a crop with clean (pest and disease free) plants. Always clean up before, after and during a crop. Prevent algae from growing in drains, channels and in other areas of the greenhouse. Control weeds on your farm. Work with neighbours to control weeds around the area. Clean clothing, footwear and equipment as well as gloves, disposable coveralls and “booties” and footbaths, all help to reduce the risk of spreading pests and diseases. Complete jobs in younger, pest free plantings before going into older crops. Do not move from an infested greenhouse to a clean crop.

Environmental control

Providing the right environment for the crop is one of the most important parts of growing a healthy productive crop. The level of light, the day and night temperatures, the relative humidity, the amount and frequency of irrigation, the nutrition and air quality all influence crop growth. Controlling these factors is important. Large variations in growing conditions can also reduce plant productivity and increase pest and disease problems. For more information refer to Structures and Technology.

Knowing the pest

Effective management of pests is dependent on knowing the pest. Not only is correct identification critical, but you need to understand the life cycle of the pest, at what stages they are most vulnerable and what specific management strategies are available. Integrated Pest Management is about using the most effective and lowest impact combination of strategies to control crop pests.