Pest forecasting (prediction)

Pest prediction must consider several intrinsic characteristics of the pests and the determining environmental and host factors. Most pest prediction models consider the phenology of the pest and its host. Accurate prediction of pest infestations before they occur is desirable in pest management programmes so that control measures can be planned with maximum efficiency. Pest dynamics show variations in timing and intensity depending on location and season.

Pests in agroecosystems are undergoing rapid environmental change due to changing cropping systems and a variety of management interventions. As a result, plant pests show a higher degree of instability in population levels. Pests vary in their biology and in their response to their environment. Pests in colder climates generally have discrete generations and dormancy periods in their life cycles, whereas in warmer climates most species show polymodal patterns of occurrence, with multiple generations in a year, due to continuous reproductive opportunities and food availability. On a global scale, seasonal temperatures and precipitation patterns are important factors determining the distribution of organisms.

Globally, an important outcome of understanding population dynamics is to strive for a predictive capability to make appropriate management decisions. Successful predictive techniques are those that are as simple as possible and based on knowledge of the biology and ecology of the pests of concern.

Due to climate regulation, the occurrence usually takes place in a relatively short period of time and is not too difficult to monitor. Pests that survive on alternative hosts can be sampled so that an estimate can be made of their probable pest density on the main crop.