Pest Threshold

A threshold level above which unacceptable damage or harm will occur to a turfgrass surface. Setting a threshold for pest (which is a generic term for diseases, animal pests and weeds) infestation is part of the approach taken in Integrated Pest Management. This can help to reduce unnecessary usage of pesticides, but also to focus a grounds manager’s attention on making best use of physical resources and technical knowledge.

Levels of pest infestation below the threshold can be tolerated, although this doesn’t mean that the extent of the infestation and damage is ignored, but actively monitored to identify the trend which is occurring. This will influence the types of control which may be needed to keep the infestation within acceptable levels as well as what might be needed if the threshold level is exceeded. The latter situation can occur quite rapidly in some situations where swards are under stressed conditions, certain grass species (and cultivars) are present, and the environment for disease activity is high.

For many surfaces, the maintenance of acceptable levels of pest within a turfgrass surface can be achieved through good cultural and physical means. However, as the standard of surface increases, especially up to Elite level then the threshold level for pests will typically be set very low, meaning that it is much harder to maintain infestations within an acceptable threshold level without resorting to biological and chemical controls.