Economic damage vs control: the thresholds
Horticulture generally operates within a less than natural environment because market expectations and activities are also in force. In horticulture, there are outcomes that an enterprise expects or needs to be financially viable. This translates into a certain quality.

An IPM program must build these expectations into the way that pests and problems are dealt with. The implications of an outbreak of a weed or disease must be diagnosed and accounted for. For each situation, the possible detrimental outcomes will have been calculated already as part of your IPM. This way you will be able to determine the urgency of action required and assess the impact on the business viability.

Pests and diseases have different advantages or disadvantages within a horticultural setting than in a more natural environment. Pest populations would normally fluctuate, their numbers getting larger and fewer according to factors such as climate, presence of control mechanisms such as predators, food supply etc. As the population rises, its food source is depleted and populations of natural predators build up.

This also acts in reverse. The predator's food source is depleted, the pest's food source is now plentiful and pest populations can rise again.

In this way, a constant balance is being maintained, with the density of insects fluctuating within limits. This is sometimes referred to as the General Equilibrium (GE).