Introduction

An important objective of studying insect migration is to develop forecasting systems to predict damaging pest events in time for preventive action to be taken. Operational forecasts are prepared for a variety of decision makers to strict deadlines and the forecasters have to work within the limitations imposed by current knowledge, hypotheses, communications and budgets. They are dependent on pest monitoring for evidence of the current situation and these datasets are inevitably incomplete. Additionally, in many if not all cases, the population dynamics of the pest are imperfectly understood, so that the basis of forecasting is flawed. It follows that forecasters should seek results from population studies that would improve their predictions.

Migrant-pest forecasters have concentrated on predicting the temporal and spatial distribution of pests, as well as changes in severity of attack, as discussed below. They have paid less attention to understanding how users (finance officers, agrochemical manufacturers and retailers, plant protection officers, farmers and pastoralists) seek to achieve better control. There is, however, a growing awareness that forecasts need to be written and evaluated with the users' requirements in mind, if they are to influence decisions.

This chapter shows how entomological studies are used in forecasting of the Desert Locust Schistocerca gregaria, and gives examples of advances arising from recent research and technological changes. It outlines current attempts to improve the accuracy and utility of these operational forecasts and examines approaches adopted for other species.